Plessey Company History

A résumé of the history of Plessey

Hugh Culverhouse was for some years a Plessey employee as a radar engineer, but, more significantly, Sir Allen Clark was his uncle, and Sir John and Michael Clark are his cousins. He has thus been in a privileged position in compiling this history of Plessey. Sadly Sir John died in 2001, but Hugh's interest in the history of Plessey goes back 30 years, during which time he was able to access not only the memories of Sir John but also those of other family members who were alive in the early days of Plessey. Hugh is, however, particularly indebted to the assistance he has received from Michael Clark and from Sir John's widow, Lady Olivia Clark. As Hugh says "It would be sad if such an important part of British 20th century industry also disappeared from memories and history books".

Compiled by Hugh Culverhouse

1917-1919: a new company is founded

Plessey began in 1917 as a manufacturer of jigs and tools, with premises in Holloway and 7 employees by 1919. The company was NOT founded by Allen Clark. His father, Byron George Clark, had played an important role in supporting the business of the young Plessey Company, and he bought a share from one of the founders, W.O. Heyne, and it was not until 1921 that Allen Clark joined the company. But the Clark family was so central to the development of the Plessey Company from beginning to end that some extra background information would be most appropriate.

The late Sir Allen George Clark, born in Brookline, Massachusetts, USA, in August 1898, came over to the UK with his family in 1910, his father Byron George Clark having been appointed European Director of the great American firm, The United Shoe Machinery Company, with the terms of reference to "Buy or Bust everybody in the shoe machinery business in Europe" at that time. Byron accomplished this mission and retired in 1920 to London. At this stage, he had already become involved with the young Plessey Company by virtue of his acquaintance with W.O. Heyne.

Byron's son, Allen, was sent to Felsted public school in Essex but ran away in 1916 to join up, and was taken on in the London Scottish. After the rapid training of that time, he found himself in France at the Battle of the Somme where he rose to the rank of Regimental Sergeant Major in the field in a very short time, but he was hospitalised with wounds and shell-shock. Recovering, he joined the newly fledged Royal Air Force (formerly the Royal Flying Corps) in 1918 for training as a pilot, was sent to Egypt and finally commissioned by the end of the war. On demobilisation, he tried various jobs but did not settle until 1921 when he joined the Plessey Company at the suggestion of his father.

  • 1917: the birth of Plessey on 11th December 1917 at 9, Bell St., Marylebone. Four shareholders were Thomas Hurst Hodgson, Raymond and Plessey Parker (brothers), and C.H. Whitaker. The one employee was William Oscar Heyne, a 28 year old German-born engineer, educated initially in Manchester, then in Germany from 1907 - 1909, who had been interned at the outbreak of WWI on the Isle of Man, but he was released on condition he found a job of "national importance". So he went to London and worked for a piano machinery company. Hurst Hodgson was impressed with Heyne's talents as a production engineer and salesman. Plessey was formed to give scope to his talents. Heyne never became naturalised.
  • 1917: the name Plessey originates both from the name Plessey Parker and also the place of origin of Heyne's wife Nancy in Plessey, Northumberland.
  • 1918: Heyne does work for other small companies in which Hurst Hodgson has interests, including British Electro Chemists which galvanised steel. One of BEC's shareholders was an American called Byron G. Clark (B.G.), who was the European representative of an American company called the United Shoe Machinery Company. BG was also Chairman of the Hubert Eyelet Company (source: Allen Clark's brother-in-law, Ray Culverhouse, 8.8.1980).
  • 1919: Plessey has moved into an old laundry in Holloway, previously occupied by BEC, which had gone out of business. They had 6/7 employees and 2 rooms totalling 800 sq.ft.. Nominal capital was £3000 (2900 x £1 ordinary shares plus 2000 x 1/- deferred shares).
  • 1919: B.G. Clark becomes a Plessey shareholder, buying 640 shares.

The 1920s

In 1921, B.G. Clark's son, Allen, started working for Plessey, thereby starting a family connection which was to remain throughout Plessey's existence. In 1925, B.G. Clark became Chairman, while Allen Clark became joint managing director with O.W. Heyne. The company moved from Holloway to Ilford, where the headquarters continued to operate until the late 1960's. In 1922, Plessey won an order from Marconi - another Essex (Chelmsford) company - for the manufacture of crystal radio sets for domestic use. This order for 50 - followed by others for more crystal sets and later for valve receivers - was the first hint of the part Plessey was to play in the radio and electronics industry. It was also the foretaste of the policy the company was to adopt of selling to other manufacturers, never direct to the consumer. Sub-contract production, particularly of radio and television receivers, was to become a major part of the firm's activities. The other growth point for Plessey in the 1920's was the manufacture of components for the radio industry.

Allen Clark realised that total production of sets by each manufacturer - a common practise at that time - resulted in an expensive end-product. By mass-producing standard components and selling them to the set makers, Plessey could reduce costs and develop a sound business. This twin policy of component-making and sub-contracting kept the Plessey name out of the limelight.

  • 1920-1925: William Heyne is Plessey Chairman and Managing Director.
  • 1921: B.G. invited Heyne to his house in Netherhall Park Mansions, Hampstead, and introduced him to his son, Allen, an American by birth but educated at Felsted, Essex. BG urged Heyne: "See what you can do with this big fella! Try and make an engineer out of him!". And so Allen Clark became the Plessey Company Secretary on a salary of £4 a week and BG transferred his 640 shares to Allen. BG had to frequently intervene to resolve disputes between Allen (AG) and Heyne, but the business relationship flourished over the years, Allen having the brilliance to win contracts and Heyne having the brilliance to meet the tough production requirements set by Allen.
  • 1921: Plessey's main work was making jigs and tools for the British United Shoe Machinery Company, a subsidiary of the United Shoe Machinery Company in America. B.G. put up the money for Plessey to buy the machine tools needed to fulfil the contract. Plessey's turnover was under £2,900 and the company made a loss of £200.
  • 1922: B.G.'s had two commuting (Theale –- London) friends Mr. Norman de Maid Watsham and Mr. Andrew H.S. MacCallum. The The former had founded Watshams Ltd, 33 King Street, Covent Garden, London WC2, in about 1919, a company which constructed power lines, sub-stations etc., and the latter worked for Marconi, who were looking for firms to manufacture radio sets under contract. . With this work in mind, Watsham and MacCallam formed a new company British Radiophone Limited (BRL), registered on 13th June 1922, possibly with financial support from Byron Clark, although Clark was not a founding director. Watshams, rather than BRL, put in a tender for the Marconi work, possibly only because they had company headed notepaper for the tender whereas BRL had not yet had any printed. They  won an order worth £30,625 on 4th July 1922 to make Marconi 'Crystal Junior' and 'Crystal A' crystal radios and 'V2' valve receivers, and they sub-contracted the order to BRL for manufacture.  BRL then sub-contractored, of course, to Plessey. Commercial radio had started; the BBC was soon to be founded, and Plessey was part of it. Byron Clark, Watsham and MacCallum had got themselves into a very cosy position. William Heyne was now beginning to show his paces, meeting the orders won by Plessey. Watshams Ltd continued to operate until it was taken over by Hawker Siddeley in 1977.
  • 1923: Plessey, with over 200 employees, moves from The Old Laundry, Holloway Road, to Ilford. Plessey had no money to buy the Ilford site, the asking price being £20,000. Byron Clark instructed William Heyne to offer just £7,500 for the property plus contents, and the offer was accepted! BG raised £5,000 through a bank manager acquaintance, and the rest was raised by BG and Heyne personally.
  • 1924-5: Plessey's turnover was £110,000. Plessey always asked for cash from customers within 7 days, but took up to 7 months to pay themselves! Marconi was often needed to meet wage bills at Plessey.
  • British Radiophone Ltd which had moved in 1923 from 36 Wybert Street, London NW1 to 33 King Street, London WC2 (where Watshams also was) was wound up after 2 EGM's in February and March 1925. By coincidence, there was also a British Radiophone Company in existence, based in Nottingham, which was also being wound up at this time and which had nothing to do with BRL!
  • 1925: Marconi withdrew its shareholding in Plessey.
  • 1925 (December): Plessey reorganises and B.G. Clark becomes Chairman (till 1927). Allen Clark and Heyne become Joint Managing Directors.
  • 1926: Percy Packman joins Plessey for £5-10 a week who later designed a radio tuning condenser of such quality that the competition was wiped out on cost and performance. Packman was one of the many engineers who built up Plessey's intellectual capital throughout its history. He registered more than 250 patents. But the most brilliant engineer remained Heyne.
  • 1927: Henry Morgan, a financier, becomes Plessey's Chairman (till 1944), having come from Marconi and stayed on the Plessey board after the split with Marconi at BG's request.
  • 1927: Allen Clark becomes a British subject.
  • 1928-29: Plessey wins orders for candlestick telephones from the Post Office and other orders from the Air Force, the car industry and Jensen cigarette lighters. But Plessey's policy of sub-contracting kept its name out of the limelight; AG's comment was "You take the publicity and I'll take the cash!".
  • 1929: John Logie Baird turned to Plessey to produce the first production quantities of his television receivers. So Plessey starts building televisors, for sale at 25 guineas each, and the television world had started.
  • 1929: Plessey produced Britain's first ever portable battery radio, called the 'National', which was bought by Symphony. Columbia also placed an order for a similar radio. Allen Clark was introducing his concept of "mass production".

The 1930s

Business was growing fast. Allen Clark was still learning, but he was a natural salesman and one of nature's bosses, and this was beginning to show. BG had to often mediate in disagreements between AG and Heyne. The core business was radio components, orders being placed by Columbia, Symphony, Pye and even Marconi. Plessey had by now invented mass production, underselling its competitors and still making large profits. New horizons were appearing with the use of the thermionic valve, and two-way radio was starting. Designing and making equipment was getting into its stride. Plessey could clearly not market radio and television sets without competing with some major customers, but Allen Clark was early in spotting the possibilities of professional electronics. Two-way mobile radio equipment was designed, to be followed by more advanced communications equipment and by aircraft navigation equipment. There was a hint, too, of the role which Plessey was later to play in telecommunications. It was fast becoming one of the largest suppliers of telephone instruments. Allen Clark, a firm proponent of licensing and know-how agreements, signed up to produce products of major importance to aircraft manufacture and operation, which put Plessey in the front line of industry when war broke out in 1939.

  • 1933: Plessey signs its first licensing agreement in USA with Jensen Radio Manufacturing Corporation of Chicago covering loudspeaker designs.
  • 1934: Plessey begins research into materials and hired a second graduate (the first didn't stay) called Geoffrey Gaut.
  • 1935: Plessey has around 3000 employees.
  • 1936: AG and Heyne fly to USA and sign up 3 of the most crucial licenses in Plessey's history: with the Breeze Corporation for aircraft radio transmission screening and cabling, meaning Plessey had joined Breeze in becoming one of the world's first companies to use multi-pin sockets and prefabricated wiring systems; with the Federal Laboratories for the Coffman aircraft cartridge starter (later useful to get British aircraft quickly started to fight WWII enemy aircraft attack); and with Pump Engineering Service Corporation for the manufacture of aircraft fuel pumps. The Pump Engineering Services Corporation manufactured an aircraft fuel pump known as the Pesco pump which Plessey subsequently manufactured and which was fitted in all the Merlin engines. Because of its unique pressure-loaded bearing, which technically outshone all its competitors, it later became the foundation of Plessey's aviation component business and, after the war, its hydraulic pump business. Plessey Hydraulics supplied virtually all the hydraulic pumps for the post-war boom in tractor production in Europe.
  • 1936: Plessey had won orders from the Air Ministry for aircraft transceivers (TR9, R1154, T1155) which were redesigned by Plessey for mass production.
  • 1937: AG secured a huge contract with the Air Ministry Contracts Department to make bomb casings.
  • 1937: Heyne and AG told their Chairman, Henry Morgan, of the financing needed for future expansion. As a result, Morgan had shares issued on the London Stock Exchange. On March 17th, Plessey become a public company.
  • 1938: Plessey's turnover was nearly £2,000,000.
  • 1939: Plessey has 5000 employees.
  • 1939 (early September): AG and a co-director went personally to Germany to collect the last few vital items ordered by Plessey to complete an order for new machine tools for shell-case production. They took it apart and brought it back to England in their luggage, arriving September 2nd (war was declared on Sept. 3rd).

The 1940s

During the war years, Plessey's growth and direction of activity were outside the company's control: there were other overriding requirements. But peace brought Plessey back on course. Many wartime activities were abandoned; shadow factories were closed, and by 1947, the number of employees had fallen from over 10,000 to 7,000 in 1947.

It must have been during these early post-war years that the next steps in the Plessey development were planned - the move from being a secondary manufacturer to a primary manufacturer. This is the more remarkable when one recalls that two of the company's established activities, component manufacture and the sub-contract production of radio and TV sets, were experiencing an immense upsurge. Yet, by the 1970's, the company had completely abandoned the sub-contract work for domestic markets and virtually withdrawn from the manufacture of many entertainment-type components. This was just as well for Plessey, considering the later state of the consumer electronics market in the 1960's. but it suggests a foresight and some ruthless decision-making in the 1940's at the very time when this section of the business was enjoying boom conditions.

  • 1940: The Air Ministry persuaded AG and Heyne (still joint Managing Directors of Plessey) to build a new factory at Swindon. Plessey also took over a factory in Cardiff.
  • 1940: Plessey Ilford was bombed in the Autumn. AG persuaded the Air Ministry and London Transport to let him use the new 5 mile extension to the underground Central Line between Leytonstone and Gants Hill as a wartime factory. The conversion of the Underground was completed in March 1942 at a cost of £500,000, giving Plessey 300,000 sq.ft. which required 350KW of lighting alone! The work of Plessey in the tunnel producing vital components was a major contribution to the war effort.
  • 1940: Plessey acquires Caswell House, just outside Towcester, Northants, which was to serve as a safe house for its research laboratory. Geoffrey Gaut and his half dozen research colleagues moved in.
  • 1940: A Plessey fuel pump is installed on the world's first jet engine.
  • 1940: Plessey's turnover was nearly £4,000,000.
  • 1941: Plessey has 8,500 employees.
  • 1942-45: AG devoted himself to Plessey's war effort seven days a week, and his family rarely saw him.
  • 1942: Percy Packman, a pacifist, refused to have anything to do with armaments and left Plessey.
  • 1944: Plessey's turnover was nearly £7,000,000 and had 11,500 employees.
  • 1944: Henry Morgan died. AG became Chairman and Managing Director until his death in 1962.
  • 1945: Plessey has 11,000 employees.
  • 1946: Byron Clark dies; William Heyne had suffered from the war years, had heart trouble and then meningitis, leading finally to his retirement. After striving to meet demands in the war, Plessey was now struggling to avoid collapse. But AG was in his prime! The company was to concentrate on radio, TV and electrical components. Swindon and Ilford remained open, but employees fell to 6,000.
  • 1946: Bedford Attwood joins the Plessey board, with responsibility for reorganisation; Jack Mallabar joins Plessey board as financial director (following Henry Morgan).
  • 1947: Plessey has now only 7,000 employees. But Plessey soon regained its position as the largest component manufacturer in the Commonwealth.
  • 1947: AG won an order from EMI for at least 100,000 radio and TV sets.
  • 1949: Plessey enters the industrial hydraulic field.
  • 1949: AG's elder son, John, joins Plessey after working for MetVick and P.R. Mallory Inc. in USA. He was appointed as head of Plessey's Irish plant.

The 1950s

As semiconductors took off, Plessey's business expanded, and by 1959, the workforce had grown to 20,000. The business trend of the 1940's of converting Plessey into a primary manufacturer continued through the 1950's. Allen Clark was preparing the company for some major takeovers which would come to fruition in the 1960's.

  • 1950: AG's second son Michael joins Plessey after working for Ford at Dagenham and Bendix Aviation in the USA. He was appointed head of the budding Electronics Division which subsequently became Plessey Electronic Systems. Teddy Underwood joins Plessey from GEC.
  • 1950's: Business fluctuated dramatically thanks to stop-go government economic policies and purchase tax iniquities. Geoffrey Gaut leads research to meet the challenge of the future and was persistently soliciting funds from AG to pursue new lines of inquiry. By 1950, there were 50 people at Caswell working with ceramics, piezo-electric materials, magnetostrictive ferrites, radar-absorbing materials, tantalum capacitors.
  • 1951: Michael Clark heads the new Plessey Communications Division, after being dropped in at the deep end by AG when Plessey fell behind in developing new VHF and UHF communications equipment. Senior managers John Cunningham and Raymond Brown formed Racal and left Plessey. In the following years, Plessey's sales of communications equipment to the armed forces grew substantially.
  • 1952: Plessey opens the first pure silicon plant in Europe. At the time, however, it was not realised just what a crucial development this was in Plessey's history. Plessey invented the expression "solid-state technology".
  • 1953: John Clark is appointed to the main board of Plessey.
  • 1957: Plessey begins manufacture of semi-conductor transistors (an idea first conceived in 1948) at Swindon after AG had achieved a license agreement with US company Philco in 1951 and the two companies had set up a joint business called Semiconductors.
  • 1957: Plessey manufactures the first VHF/UHF airborne radio in the UK.
  • 1958: Plessey wins its first contract for real integrated circuits from the Ministry of Supply's Malvern radar research centre (R.R.E.).
  • 1958: A new factory was built at Cheney Manor where large-scale semi-automated production of high-frequency surface-barrier transistors began. The Philco transistors were based on germanium, but Geoffrey Gaut and Derek Roberts believed the future lay in silicon. They were right!
  • 1959: Plessey had 20,000 employees and sales were £30,000,000. John and Michael had become AG's executive lieutenants but did not always agree with AG; in particularly, they wanted to push more towards in house high technology than continue relying on licenses from US companies.

The 1960s

The company was gradually becoming a business with its own in-house high-technology capability. Rapid growth in size in the early 60's brought problems of rationalisation, and, following the McKinsey (US management consultancy company) review which had been commissioned by John Clark in 1965, the businesses of Plessey were divided into "Groups" as follows:

Automation Group, based in Poole with divisions also in Liverpool, Towcester and the Netherlands; businesses including Data Equipment, Data Handling, Data Processing, Systems Development and Traffic Control and Memory Systems.

Components Group, based in Swindon with divisions also in Chessington, Ruislip, Towcester, Titchfield, West Lothian, Liversedge, Caswell; businesses including Ceramics, Chemicals, Metallurgics, Connectors, Components, Mechanical Products, Wiring, Garrard Engineering (top quality record decks and changers), Product Assessment laboratories, Allen Clark Research Centre in Caswell.

Dynamics Group, based in Ilford with divisions also in Romford, Swindon and Titchfield, businesses including Hydraulics, Electrical Systems and Mechanical Systems.

Electronics Group, based in London WC2 with divisions also in Ilford, Addlestone, Cowes, Beeston, Bridgnorth, Taplow, Templecombe, Braxted Park, West Leigh, Roke Manor; businesses including Radio and Electronics Systems, Radar, Microwave and Transmission, Research and Development, Command and Control, Sonar Systems.

Telecommunications Group, based in Liverpool with Divisions also in Chorley, Kirkby, London, S. Shields, Wigan, Beeston, Nottingham, Sunderland, N. Ireland; businesses including telephones and other communications and exchange systems; overseas offices in Hong Kong, Nigeria, Ireland and Venezuela.

Australia Group (Plessey Pacific Pty Ltd.) based in Sydney and Melbourne with Divisions including Automation/Electronics, Components, Dynamics, Telecommunications),

South Africa Group (Plessey South Africa Ltd.), based in Cape Town  with divisions including Telecommunications and Automation Sales, Components sales, Tellurometer/Viatec sales, Marine and Industrial Services, telephone manufacturing, with also Plessey Telecommunications in Rhodesia/Zimbabwe.

International Group, based in London WC2 (with business interests in Ireland, Africa, Canada, Europe, Far East, Middle East, New Zealand, South America and USA).

The Automation Group quickly became amalgamated with Electronics.

The contributions of the divisions to the total Plessey turnover in the company's Golden Jubilee year, 1967, was as follows:

Automation: 6% with 3,500 employees,
Components: 21% with 13,500 employees,
Dynamics: 7% with 3,000 employees,
Electronics: 19% with 9,600 employees,
Telecommunications: 33% with 25,000 employees,
Overseas: 14% with 9,700 employees.

During the 60's, Plessey built up its R&D capability by developing R&D labs at Caswell, Roke Manor, Taplow ,Havant and Poole. Amongst its claims to fame, Plessey R&D sites developed the programming language IDA.

Plessey rode on the back of the Post Office's mammoth investment spending and orders for telecommunications equipment, which increased at a rate of some 18% a year during the 60's. Under the bulk supply agreement in force until 1969, Plessey, GEC and Standard Telephone (STC) shared these Post Office orders on a 40-40-20 basis.

In the late 1960's, Lord Weinstock of GEC beat Sir John Clark's Plessey bid to take over English Electric during the restructuring of the electrical industry by Labour's Industrial Reorganisation Corporation. Relations between Weinstock and Sir John were "strained" from this time onwards. The strain was to be felt over the next two decades.

  • 1960: Plessey takes over Garrard, adding 10% to turnover.
  • 1961: Allen Clark is knighted.
  • 1961: Plessey decided to run down its manufacture of radio and TV.
  • 1961: Philco pulled the plug on the Semiconductors business, leaving Plessey to continue alone. The deal had been a disaster (it was to prove to be AG's last big license deal). In spite of this and reduced military sales, the company was rich, with a cash mountain of £16,000,000.
  • 1961: Plessey merges with (or effectively takes over) the British Ericsson Telephone Company and Automatic Telephone & Electric (AT&E) for £2.75m, thus doubling Plessey's size overnight. Thus were acquired Plessey's sites at Liverpool and Beeston. This should have been AG's finest hour, but he had been diagnosed with cancer. John Clark becomes Joint Managing Director and Michael Clark Deputy Managing Director of Plessey. Sir Harold Wernher becomes Deputy Chairman.
  • 1962: Sir Allen Clark dies on 30th June. Caswell was renamed the Allen Clark Research Centre in his honour. Harold Wernher becomes Chairman (till 1963).
  • 1962: After boardroom disagreements, Jack Mallabar, Bedford Attwood and Alexander Roger resign after losing a vote of no confidence in John Clark as the new MD. Wernher appoints Harold Watkinson (former Defence Minister), Lord Kilmuir (ex-Lord Chancellor) and Field Marshal Lord Harding of Petherton to the Plessey board. John Clark becomes Chairman of both Ericsson and AT&E.
  • 1963: Lord (Rt. Hon. Earl of) Kilmuir takes over from Harold Wernher as Chairman of Plessey (till 1967). Teddy Underwood is in charge of Plessey Overseas. Plessey's profits nearly double to £11.5m.
  • 1963: Plessey takes over Ducon in Australia (telecommunications equipment and components) electrical and electronic components manufacturer).
  • 1963: Plessey starts development of an electronic telephone exchange TXE2, scheduled to be ready by 1967.
  • 1964: Plessey takes over Instrument Manufacturing Corporation of South Africa.
  • 1965 (January): Plessey takes over Rola Holdings in Australia (electrical and electronic components manufacturer, such as TV and radio components). The Telegraph Condenser Company Ltd (UK) was also taken over.
  • 1965 (March): The McKinsey report: see above, under "The 1960's".
  • 1965 (April): Plessey takes over Decca's data handling and ground-radar and heavy radar divisions based at Chessington, Surrey, and Cowes, Isle of Wight, for £4m. The radar business then needed more space and Plessey took over the rental of a site at Addlestone, Surrey, which had been previously used by two bus companies (and thus was born the Plessey Radar Addlestone site).
  • 1965 (May): Plessey takes over the Telegraph Condenser Company Ltd (UK) for £3m.
  • 1965: Allan Robb becomes Plessey Personnel Manager, and the days of "hire and fire" began to disappear.
  • 1966: Swindon starts manufacture of MOS integrated circuits, making Plessey the first European and fourth global company to manufacture such microchips. The business is firmly supported by John and Michael Clark, but the profits did not start coming until the early 1970's.
  • 1966: Teddy Underwood retires from main Plessey board. Warren Sinsheimer who becomes Chairman of Plessey Inc. (after joining Plessey in 1956) and in 1969 takes the place vacated by Teddy Underwood on the Plessey board.
  • 1966: Garrard wins the Queen's Award for Export.
  • 1966 - 68: John Clark has his first fears of a forced merger with GEC. There followed many "discussions" with Anthony Wedgwood-Benn of the Industrial Reorganisation Corporation, Anthony Crosland of the Board of Trade. Plessey had a rough ride, but after fighting back with the takeover of the numerical controls divisions of both Ferranti and Racal, as well as Diac's NC business. Thus was born Plessey's site at Poole.
  • 1967: Plessey is 50 years old. Lord Harding takes over from Lord Kilmuir (following his untimely death) as Chairman of Plessey (till 1970). John Clark is Deputy Chairman and Managing Director, and Michael Clark is Deputy Managing Director and Director of the Telecommunications Group.
  • 1967: By now Plessey had 26 out of 32 PO orders for Crossbar telephone exchanges and 28 of the 67 orders for smaller electronic exchanges. Even Arnold Weinstock of GEC was forced to come to Plessey for a license agreement to make "5005" exchanges!
  • 1967: John Clark signs a 5 year technical agreement with the USSR for the exchange of specialised knowledge and joint co-operation in the fields of automation and electronics. Plessey now has trading companies operating in Canada, East and Central Africa, France, Italy, Lebanon, Malaysia, Netherlands, Singapore, Switzerland, USA and Germany.
  • 1967: Plessey takes over Italian hydraulic company Turolla Spa.
  • 1967: Plessey won a contract to make fuel systems, power systems and actuators for the Concorde supersonic jet airliner. Plessey Automation is the largest supplier of computer memories in Europe. The Components Group is the biggest electronic components manufacturer in Great Britain and one of the leading producers in the world.
  • 1967: Plessey has 68,000 employees including 6,500 in research and development. Turnover was £145 million and profits before tax were £13,8 million.
  • 1968: Concorde 001 takes off to set in motion supersonic passenger travel. In it are many Plessey components, including fuel systems, power systems and actuators.
  • 1968: ICL was born out of the business of ICT (International Computers and Tabulators), owned 18% by Plessey, 18% by English Electric. Plessey had seen the convergence of telecomms electronics and data processing. Micro-electronics was to be the core of the new technology. How right can you be? Michael Clark was quick to realise that the development from components to 'black boxes' was the crucial advance towards the creation of electronic systems and would thus take Plessey into an entirely new league of major international players.
  • 1969: Plessey takes over American semiconductor and space industries company Airborne Accessories.

The 1970s

The growth in Post Office orders in the Telecommunications field during the 60's could not be maintained during the 70's following retrenchment at the Post Office.

Plessey's semi-conductor and component interests remain a major part of Plessey, but they only ever made a minor contribution to profit. The semi-conductors business was a major loss-maker from the very beginning. The real money was now to be made in systems, not components, and the most profitable businesses were to prove to be in the fields of defence electronics, EDP (electronic data processing) and telecommunications.

During the mid 70's, the autonomous Plessey defence business, originally the Electronic and Equipment Group, became Plessey Electronic Systems Ltd (PESL). The remaining Decca radar business (excluding marine radar) had also been acquired and was integrated into PESL. Michael Clark became PESL Chief Executive. PESL went on to make 30% of the Plessey Group total profits, which was out of all proportion to the capital it employed from the Plessey Group. PESL contributed 28-32% return on capital to the benefit of corporate results. The Telecommunications business accounted for more than 50% of the Plessey Group's profits (source: Daily Telegraph, 5.1.1976).

  • 1970: Plessey takes over Alloys Unlimited Inc in USA.
  • 1970: John Clark takes over from Lord Harding (aged 75, died January 1989, aged 92) as Chairman of Plessey. Michael Clark becomes Managing Director.
  • 1971: Plessey installed its 100th TXE exchange and telephone sales topped £100m. Allen Clark's optimism after the Ericsson and AT&E takeovers had been vindicated. Other parts of Plessey were also coming good, many of them under the wing of Michael Clark, who had been particularly effective in building up Plessey's defence and aircraft business. The first "Hubcap" radar system was shipped to Australia to defend the whole of its east coast.
  • 1971: Plessey's sales jumped to £258m. Garrard won the Queen's Award for Exports, and the Swindon silicon chip business was finally making a profit. But the Numerical Controls business was suffering. 1800 jobs were saved by Plessey at Alexandria, by Lake Lomond, but cutbacks had to be made. In September, the site was closed with 170 layoffs.
  • 1971: The Plessey workforce was now 85,000 world-wide.
  • 1971: John Clark is knighted.
  • 1972: Plessey lost money in computer memories, numerical controls, semi-conductors and the United States. John Clark set about a reorganisation of the company into businesses.
  • 1973: Plessey Telecommunications Research Ltd (Taplow Court) design and implement, with assistance from Computer Analysts and Programmers Ltd., develop a compiler for the programming language CORAL 250 (an enhancement of Plessey's CORAL 66). The new language is to exploit the architectural features of the Plessey System 250, the processing system selected by the Ministry of Defence for the Ptarmigan military communication project.
  • 1973: Plessey Group profits reached new record levels of £31.5 million (+42%) on a turnover of £325 million (up from £283 million). There were 60,021 UK employees. The various businesses performed as follows:
      Telecommunications and Transmission products: turnover £142 million (44%),
      Electronic equipment (inc. radar and radio): turnover £73 million (22%),
      Aerospace equipment and industrial hydraulics: turnover £29 million (9%)
      Electronic and mechanical components: turnover £81 million (25%)
    Of the total turnover of £325 million, 70% was from UK operations, 30% from overseas. £30 million was being spent annually on R&D throughout the world.
  • 1974: Plessey Navaids is formed under Plessey Radar (Addlestone). The General Manager is Stan Kyte. In March, they win a contract for £3 million for electronic equipment at Cairo Airport, and wish to tackle an £85 million market for airfield electronics packages. In May, a contract worth £850,000 is won to supply an ILS (Instrument Landing System) to China.
  • 1974: Plessey invests £500,000 to make its semiconductor plant at Swindon one of the best equipped semiconductor facilities in Europe. Further expenditure is planned for the ultra-fast Process III technology and MOS.
  • 1974: Plessey Memories wins a £1.1 million order from Japanese firm Oki Electric Industry Co. of Tokyo for ferrite core memory systems which will be incorporated into their minicomputers. The memories are 8 kiloword 18 bit systems with a 650ns cycle time.
  • 1974: Plessey's digital telephone exchange TXE4 was ready; a £17m contract was won from the MoD ("Ptarmigan"); an instrument landing system (ILS) was selling worldwide, although Plessey had lost out on the selection of the international standard for a microwave landing system (MLS) to USA (it was, however, generally accepted by those involved technically that the Plessey proposed standard offered a better performance); Caswell won the Queen's Award; but employees were down from 85,000 in 1971 to 75,000 worldwide (largely as a result of significant improvements to productivity brought about by the changes from electromechanical technology to solid-state, rather than as a result of a genuine reduction in business).
  • Plessey wins an order worth £500,000 to supply telex switching equipment to the Libyan Post and Telecommunications Corporation.
  • 1974: Allan Robb is killed in an aircrash at the age of 44 on a visit to Peter Parmella at Kembrey Street, Swindon. Parry Rogers is recruited from IBM to take over as Personnel Director. Frank Chorley comes from GEC to become MD of various electronic businesses.
  • 1975: Plessey Group profits are £39m.
  • 1976: Plessey Group profits fall to £34m (problems: inflation, Portugal, USA etc). Sales rose, however, to £490m.
  • 1976: John Clark establishes a Chief Executive Office comprising John Clark as Chief Executive (till 1987), and Michael Clark (Deputy Chairman), Warren Sinsheimer, finance director Eric Frye and Telecoms Managing Director Dr. Bill Willetts as Deputy Chief Executives. The product divisions and Corporate Staff then reported to the Chief Executive Office, based at Millbank, London. The role of Managing Director disappeared, but Sir John Clark remained Chairman and Chief Executive.
  • 1976: Plessey has 50,700 employees in the UK. Turnover was £490.1 million and profit before tax £34.7 million. There were 130 Plessey establishments in the UK and 250 worldwide. Plessey was represented in 136 countries.
  • 1976: Peter Marshall, the new finance director, builds up Plessey's cash resources to more than its borrowings for the first time in its history. Plessey's profits and sales rose steadily from 1976 onwards.
  • 1977: Due to Post Office cutbacks, Plessey had to make 4800 workers on Merseyside redundant, costing nearly £8m.
  • 1977: The Plessey board decides by a majority verdict to sell the semi-conductor businesses (Swindon, Towcester and Plympton) and its microchip research centre (Caswell). The new Finance Director, Peter Marshall, insists that this is necessary to reduce company debts. John Clark and Geoffrey Gaut were against the sale. After Geoffrey Gaut had sought external advice which was against the sale, John Clark managed to persuade the board to reverse their decision. A few weeks later, he was telling shareholders that the business was doing better than most of its rivals.
  • 1977: Desmond Pitcher joins Plessey from British Leyland and becomes MD of Plessey Telecommunications.
  • 1979: The loss-making Garrard is finally sold. Also sold were parts of Alloys Unlimited, the hydraulics business, the numerical controls company and the Portuguese telephone subsidiary. Plessey sold its 24% stake in ICL.

1980 - 1989

Into the 1980's and many Plessey sites flourished:

  • Poole, where Plessey dominated the Command and Control business;
  • West Leigh, for research and production of avionics;
  • Ilford, for radio communications;
  • Templecombe, for sonar research;
  • Newport, for Underwater Systems production;
  • Isle of Wight, for manufacture of ground and surveillance radars;
  • Addlestone, for surveillance radar processing systems and Air Traffic Control systems;
  • Beeston (formerly the British Ericsson Telephone Company), for telecommunications;
  • Chorley, Sunderland, South Shields and Towcester all flourished as satellite factories.

The fight for Plessey's survival built up during the 1980's. A Group policy of selling poorly performing businesses developed. In 1986, Plessey beat off a £1.2 billion bid from GEC. But in 1988, things hotted up even more.

  • 1981: Plessey's workforce is down to 47,000. The first System X electronic exchange is delivered to British Telecom (now privatised). Orders are more or less guaranteed at £120m a year for many years ahead. The Ptarmigan battlefield communications systems had been bought by the British Army, the development contract being worth £100m and the first production system £150m. The military comms system "Wavell" had also been bought.
  • 1981: 70% of Plessey's semi-conductors are exported to 45 countries, which earns them the Queen's Award for Exports (Plessey's tenth!). Plessey redoubled its commitment to R&D, improving facilities at Caswell and Roke Manor, and encouraging a new drive into what was beginning to be called Information Technology.
  • 1982: Plessey becomes prime development contractor for British Telecom.
  • 1984: Plessey is hit by industrial trouble, and the acquisition of Stromberg Carlson (telephones) in USA turned sour. The result was the first drop in profits for 8 years.
  • 1985: By now, Michael Clark is Joint Deputy Chairman of Plessey, with Lord Pennock.
  • 1985: Plessey's results for 1985 were: Sales £1.415 billion, pre-tax profits £163 million.
  • 1985: Semi-conductor sales are increasing, and giant strides are being made in opto-electronics. New manufacturing and technology centres are springing up at Edge Lane (Liverpool), Beeston and Caswell. John Clark could report at the Plessey AGM that the company had a clear focus on core businesses and the targets it had set for them. The positive situation caught the eye of Arnold Weinstock of GEC.
  • 1985: On 3rd December, Arnold Weinstock of GEC hands John Clark his plan to take over Plessey; offering 160p a share or just over £1 billion, compared to GEC's market capitalisation of nearly £5 billion. Plessey's board met the next day, resulting in John Clark's announcement: "My board is prepared, subject to further negotiations with British Telecom, to make a firm offer for GEC's interest in System X". The real battle was just beginning.
  • 1986: On January 14th, John Clark told Plessey's shareholders that GEC was a "lack-lustre conglomerate with a poor record in high technology and with a financial performance characterized by mediocrity. They need our technology to put credibility back into an unimpressive performance". But both GEC and Plessey were entirely answerable to their shareholders, and both companies were inextricably in the coils of the major customers, British Telecom, the Department of Trade and Industry and the Ministry of Defence.
  • 1986: Plessey defended itself by declaring a profits forecast far better than expected. It also tested the GEC offer in the US courts, claiming it did not comply with American securities law, but this lawsuit was lost.
  • 1986: Plessey's results for 1986 were: Sales £1.461 billion, pre-tax profits £170 million.
  • 1986: Plessey furthered its defence against GEC by claiming that 30% of its key electronics workers would leave if GEC took Plessey over. 85% of the Plessey engineers were against the GEC offer. On January 20th, the offer was referred to the Monopolies and Mergers Commission (MMC), giving Plessey effectively a 6 month respite.
  • 1986: Sir James Blyth (formerly head of sales at the MoD) is appointed Plessey Group Managing Director (he resigned in 1987 after the formation of GPT). And Sir Gordon Reece, Margaret Thatcher's former public relations consultant, is appointed special adviser to John Clark.
  • 1986: GEC's attack on the ability of the Plessey management backfires.
  • 1986: In July, GEC announced its first fall in earnings in 19 years, thereby seriously denting Arnold Weinstock's reputation. On July 16th, Plessey workers march through the City to object to the GEC offer. The Ministry of Defence is also against the offer.
  • 1986: On 6th August, the Monopolies and Mergers Commission voted against the GEC offer. The Secretary of State for Trade and Industry, Paul Channon, was forced to finally block the £1.2 billion GEC offer. Plessey could now draw breath and remain independent. Sir John Clark, at a subsequent board meeting, looks at a picture of his father on the wall and say "He would have been proud".
  • 1986 (estimated): Plessey acquires Ferranti Semiconductors, thereby creating Europe's largest semi-custom chip company. A new state-of-the-art silicon chip production facility near Plymouth is opened.
  • 1987: Software now represents a ratio of 50:50 with hardware.
  • 1987: Stephen Walls joins Plessey's board as Finance Director.
  • 1987: Plessey's results for 1987 were: Sales £1.429 billion, pre-tax profits £184 million.
  • 1987 (October 1st.): Spurred on by the privatisation of British Telecom and the BT decision to buy Ericsson's rival System Y, GEC and Plessey merge their telecommunications businesses in a jointly owned venture which should have annual sales of over £1.2 billion. Primarily, this means the merger of the System X telephone exchange businesses. But the new company, GPT (GEC Plessey Telecoms), will also embrace a wide variety of other telephone interests in an attempt to create a group offering a more powerful and competitive range of telephone systems worldwide (source: Times, 2.10.1987). The Monopolies and Mergers Commission had been in favour of this fusion of interests when the GEC takeover bid was blocked in 1986. The formation of GPT puts 48% of Plessey sales but only 13% of GEC sales outside of the parent company control. A total of 23,000 employees make up GPT, but about 7,000 redundancies are feared. Both Plessey and GEC set up plants for System X when there were high hopes of large export orders, but now they have excess capacity.
  • 1987: Michael Clark, Frank Chorley and Bill Dalziel (all main board directors) retire from Plessey, an event occasioned entirely by the GEC takeover efforts.
  • 1987 (October 2nd.): Sir James Blyth resigns as Plessey Managing Director (he was to subsequently run Boots).
  • 1988 (March): GPT is now officially created.
  • 1988: Plessey buys Sippican in USA and Leigh Instruments in Canada (defence contractor), both of which should serve to reduce Plessey's dependence on the MoD and British Telecom. Plessey also buys the Electronic Systems Division (American advanced avionics defence business) of The Singer Company (renamed Plessey Electronic Systems Corporation), Sippican (US anti-submarine warfare specialist) and British computer services group Hoskyns Group plc. Plessey's share in Elettronica in Italy was increased by £16 million from 35% to 49%. Company efficiency was improved due to the formation of GPT where jobs totalled 1800. Plessey acquired a 74% shareholding in Elsydel (Éléctronique et Systèmes SA) of France, and, together with a joint venture agreement with CAE of Spain, created Plessey Traffic Systems International Ltd.
  • 1988: Ferranti Semiconductors (Oldham) is acquired to add to the Swindon (HQ) and Roborough (Plymouth)  Plessey Semiconductors sites. Importantly (mentioned elsewhere) Caswell provided research & design and pilot production of silicon circuits for Semiconductors.
  • 1988: Plessey's profits fall 6.6% to £172 million on sales of £1,300 million. Sir John Clark said there were "good reasons for renewed confidence" with the order book standing at £1.7 billion; the Group had a cash pile of £220 million. Meantime, GEC's profit was £708 million on sales of £5,552 million. Sir John Clark's expression "I am a manager, Arnold Weinstock is a banker" is repeated.
  • 1988 (September): Plessey now has order books (inc. Plessey's share of GPT) worth £2.05 billion, which is 50% up on March 1987.
  • 1988 (October): Stephen Walls becomes Managing Director of Plessey.
  • 1988 (November): GEC joined forces with Siemens and put in a joint bid of £1.7 billion for Plessey, a bid which, if successful, would make the group Europe's largest electrical group and big enough to take on the Japanese and Americans in the vital sphere of microchip technology. Sir John Clark immediately rejected the bid, but GEC hopes that the MoD's attitude has now softened towards such a bid and that the new bid will clear British and European Economic Community (EEC, now EU) hurdles. The offer was worth 225p per share, and Plessey shares jumped 48p in 24 hours to 224p. Lord Weinstock says that none of his plans would immediately affect the 30,000 Plessey workforce. In the bid document, GEC Siemens plc states "that the acquisition of Plessey will lead to enhanced career opportunities for the management and employees of Plessey. ........The proposed arrangements will enhance the prospects for the work force of Plessey and will create additional opportunities for management, technical and professional employees".

    GEC: Sales £5.5 billion, pre-tax profits £708 million, employees 157,000                  
    Siemens: Sales £16.2 billion, pre-tax profits £818 million, employees 359,000
    Plessey: Sales £1.3 billion, pre-tax profits £172 million, employees 30,000 (excl. GPT)

    Stephen Walls, Plessey's Managing Director, declares "It doesn't make sense for Plessey to lie down and roll over". The bid hardly does justice to the £500 million Plessey has invested in acquisitions in the last 18 months alone. According to Plessey, the structure concocted by the bidders has everything to do with getting around the MMC and nothing to do with industrial logic. In reality, the bidders are planning an old-fashioned carve-up of a competitor.

  • 1988 (December): Plessey considers an audacious "Pac-Man" reverse takeover bid for GEC, whose stock market value at present is £4.7 billion. Possible parners for Plessey could be the French electronics group Thomson-CSF and the British information systems and telecommunications business STC. A foreign-based consortium bid for GEC would, however, almost certainly be turned down by the Ministry of Defence. The Monopolies Commission and the European Commission would also have to consider the detail of such a bid.
  • 1989 (January): the GEC/Siemens bid lapses after reference to the Monopolies and Mergers Commission, but the threat of a renewed bid remains.
  • 1989 (February 6th): Siemens/GEC put in a revised bid for Plessey.
  • 1989 (March): Plessey's results for 1989 were: Sales £1.655 billion (+27%), pre-tax profits £196 million (+14%), order book £2.13 billion (+23%), employees worldwide 26,000 (excluding GPT). Defence of the new GEC/Siemens bid has cost Plessey so far £31.7 million. Today, only 40% of defence sales are sourced by UK contracts, whereas 3 years ago, it was 80%. This positive development has been the result of deliberate strategy to reduce dependence on the MoD.
  • 1989 (June): Michael Clark writes to the Times: "The Plessey defence business is a vital national asset, with sales in excess of £750m and 13,000 employees. ......PESL is far stronger than Siemens in defence and has consistently whipped GEC-Marconi in competitions at home and abroad over many years. That is how we built it: by beating GEC and many other international giants contract by contract, on a dual basis of technology and price - in that order. Surely PESL must be the ideal catalyst on which to build further - not to tear down - and it cannot be beyond the wit of the powers that be to make it happen, now, in the national interest. We all know what would be the fate of this great company under Lord Weinstock. It is not yet too late to be both positive and creative by building, on Plessey, the most dynamic and technologically advanced defence electronic business in Europe". Prophetic words indeed!
  • 1989 (5th July): Plessey and GEC terminate negotiations for the sale of Plessey's 50% shareholding in GPT. The price of £825 million is not believed the be the problem.
  • 1989 (August 2nd): The Secretary of State for Trade and Industry announced that, following the report of the MMC which was published on 21st April, satisfactory undertakings have been received from GEC, Siemens and GEC/Siemens relating to certain Plessey businesses.
  • 1989 (3rd August): GEC Siemens announces a final offer of 270p per Plessey share, valuing the whole of the issued share capital of Plessey at about £2 billion. The offer of 270p is in fact less than the share price of the day. By the end of the day, GEC Siemens had purchased 113 million extra Plessey shares, giving them a total of 224 million shares or 29.9% (the limit set by the City Code on Takeovers and Mergers. Acceptances of the offer have to be received by September 7th.
  • 1989 (7th August): Sir John Clark says that the GEC Siemens offer "is totally inadequate as it still fails to recognise the value of Plessey's current business let alone its future prospects".
  • 1989 (August): Plessey is believed to be in talks with Japanese group Sony about forging a partnership in microchips. Plessey's higher microchip valuation (at present £220 million) would underpin Plessey's contention that the GEC-Siemens bid at 270p per share undervalues its prospects.
  • 1989 (21st August): Sir John Clark says that "the objective of the bidders is clear. They are attempting to secure control of Plessey without paying a full and fair price. The offer document presents a misleading account of Plessey's competitive position and a distorted analysis of its financial performance".
  • 1989 (26th August): Sir John Clark sets out the strategic objectives for the New Plessey and the actions to be taken following the lapse of the GEC Siemens bid. These plans included the disposal of their 50% GPT shareholding (valued at £825 million), expansion of the traffic management business, the development of a European Networks and Services Business, the pursuit of alliances in Defence Electronics, the pursuit of an alliance with a major Japanese semiconductor company, the expansion of the Aerospace business and the creation of a Commercial Ventures Group. He announced that, should the GEC-Siemens bid fail, he will relinquish all executive responsibilities in March 1990 to become non-executive chairman, handing over strategic and operational control to Stephen Walls, who will become Chief Executive. Such a move would end the founding family's executive links with the company.
  • 1989 (27th August): Plessey plans its future, should the bid fail:
    Plessey's stake in GPT will be put up for auction and the proceeds redeployed in expanding elsewhere;
    Plessey will not bid for Ferranti, where it holds a 2% stake, but seek to expand in Europe into radar and naval systems;
    In Traffic Management, Plessey will make acquisitions in Europe;
    In Aerospace, Plessey will open discussions with a number of companies in USA with the aim of expanding into the market.
  • 1989 (14th September): Sir John Clark circulates to shareholders: "You may now be aware that the offer by GEC Siemens plc for the share capital of Plessey contained in the offer document dated 17 August 1989 has become wholly unconditional and that GEC Siemens now controls more than 50% of Plessey. Under these circumstances, your board considers that it is in the shareholders' best interests to realise their investment in Plessey as soon as possible. Accordingly, shareholders are recommended to accept GEC Siemens' cash offer of 270p per share, as the Directors of Plessey now intend to do in respect of their own shareholdings".
  • Sir John Clark retires on completion of the takeover.
  • 1989: The name Plessey Semiconductors disappeared and the business became GEC-Plessey Semiconductors (GPS) which also incorporated the Wafer Fabs of Marconi Electronic Devices Ltd (MEDL) Lincoln.  The Ferranti element of Plessey Semiconductors went to Zetex.
    1998: GEC sold the remaining Semiconductors business to Mitel (Canadian).

Other material

For a history of the Plessey Co. Ltd. up to 1987, see "Into the Sunrise, a history of Plessey" by Berry Ritchie, printed by BAS Printers Ltd., published by James and James, Landscape Books Ltd., 75, Carleton Rd., London N7 0ET. Book reference ISBN 0 907301-X. Tel. 0207 700 0218 (This book is according to the publishers no longer available, and there was no second edition ever published to continue the history up to the takeover in 1989)

Air-Road-Sea Addlestone. JH Rowe 1992 ISBN 0 9518 658 1 1. A history of the Addlestone site from 1916 to 1988 covering Bleriot, Weymann's and Plessey

An obituary for Sir John Clark

Internet links:

Notes regarding individual Plessey sites

Information is scarce regarding the present activities at the former Plessey sites. Any assistance with further information will be gratefully appreciated.

Plessey Addlestone (Radar)

The site was originally built by Bleriot (he of flying across the Channel fame) to build aircraft. At first this may seem an odd location, but remember that Brooklands, not many miles from here, was the home of both racing and avionics in this country. Incidentally the Brooklands Museum is well with a visit. A real visit that is, not just a virtual visit.

Bleriot's use of the site did not last very long, and he was followed by Weymans to build busses and coaches. Those who are into transport nostalgia might be interested in the fact that the prototype Routmaster busses were built here, though Weymans did not get the production contract. Weymans closed in the late 50's and for a short while a company called Caddy's built taxis here.

Around 1965 Plessey, who had just taken over part of Decca to establish Plessey Radar, had to move out of Decca's premises at Chessington, and relocated to Addlestone. The inside of A, A5 and B blocks were upgraded to the standards of the day. Later K block was built, and later still L block.

Business names changed. In the early 80's the main business became Plessey Displays, then later merged to become part of Plessey Naval Systems. Other businesses that existed alongside, or spun off, included Plessey Airports.

After the GEC and Siemens takeover, the spoils were divided among themselves. Plessey Radar found itself part of Marconi Underwater Systems Ltd (a wee bit of an odd title for a business that included air traffic control consoles in its portfolio!). After a few more restructurings, the Addlestone business, which by now had had added to it parts of Ferranti, was amalgamated with the GEC-Marconi business at Frimley to form Marconi Command & Control Systems.

With a reduction in the number of staff employed on the site, parts of it had been leased out to other tenants, most notably a firm of architects. Then in July 1997, after lengthy speculation, it was announced that the site would close. Most staff transferred to Frimley, some to Farlington, and some were made redundant. The site closure was completed in March 1998.

The site was demolished in 2001 in order to build a new business park.

Addlestone text contributed by Neil Bartlett.  Additional material

Plessey Beeston (Nottingham)

The Beeston site, originally  the National Telephone Company (in 1901) became L.M. Ericsson until the Plessey takeover of Ericsson in 1961. In 1988, the site became part of the GPT business. After the GEC/Siemens takeover of Plessey, the site went to Siemens, but in 2005, GEC (by 2006 Marconi) retained an Optical Networks engineering R&D base on the site.  In 2005, there were about 320 staff on the site. The site was sold to ING Bank in 2003, and their redevelopment plans were still awaited in 2005. By 2007, the Marconi site had been taken over by Ericsson (Swedish Ericsson - how ironic) Siemens, but manufacturing remains on the site, and there is also a "Busines park"on the site. As of October 2009, Beeston site still has Marconi on site, which is still part of Ericsson, who were on the site before 1961. The Plessey Isdx which is now know as HiPath DX is still being built in Beeston by a company called SME; so the Plessey legacy still hangs on by a thread!

Plessey Caswell (Research)

The present Caswell House is one of several farm houses erected by the Duke of Grafton in the 1840's. These houses are recognizable by their spacious, regular and rational planning and their plain but sound architecture. They are characterised by a house of 3 widely spaced bays with a low pitched, hipped, slate roof and lower wings. They appear Regency (1811-1820) but were in fact built in 1841-3.

In 1939 (9th May), Caswell Farm was sold by the Tenth Duke of Grafton (trustee Mr GJR Cooper, Army Captain) to GCB Bramwell (Army Captain retired) & Mrs Bramwell.

In 1945 (31st July) the farm was acquired by The Plessey Company from Major GCB Bramwell & Mrs Bramwell.

In 1945 (12th November) Plessey leased the farm to Mrs Gaut with Mr Gaut providing surety.

Caswell Labs beginnings and success over the years is attributable to the effort and dedication of many, many people and it is acknowledged that without Sir Allen Clarks foresight and support, continued by Sir John and Michael Clark, Caswell would probably still only be a name on a map. However it was Geoffrey Gaut who (effectively) founded the labs and was the guiding figure in what the labs became. The house, for a period, was also his family home. The Plessey Caswell scientists did some amazing things and they were a credit to Plessey.

In 1968, Plessey looked at all their properties that included Caswell with view to selling off surplus land. At Caswell, this ultimately resulted in some 207 acres of the original 230 being sold. The land was sold to Sir Frederick Bolton for £45315 in August 1968. The Caswell site was thereby reduced to 23 acres.

Caswell provided research & design and pilot production of silicon circuits for Semiconductors.

After the GEC/Siemens takeover of Plessey, the Caswell site was taken over by GEC and subsequently GEC Marconi. But Marconi problems led to the sale of the site to Bookham Technology in 2002. How different the site had become under GEC management compared to Plessey management and the consequences of the near demise of Marconi!

Plessey Christchurch

Prior to Plessey, this site was the Ministry of Defence Signals Research and Development Establishment (SRDE), until the MoD colocated to RSRE at Malvern in the mid to late 70's. Much of the site had not been updated since World War II, and when the additional investment was made by Siemens after the Plessey takeover, much of the older parts of the site was rebuilt. The site was used by Plessey as the base for the Ptarmigan project.

'H' building that used to hold the directors and senior management was sold off around 2005 to a housing association.  The entire south side of the site has also been sold and as of 2010 was awaiting planning permission for combined housing and industrial units.  The Plessey logo can still (2010) be seen on plates on the doors of the now East Christchurch Sports and Social Club, still known locally as The Plessey Club.  There is still a sign in the corner of the playing fields along the lines of "Plessey Company, private property, no right of way etc"

Plessey Ilford

This was the most important of all the Plessey sites.

Towards the end of the 1980's, the workforce at Ilford was down to about 600, and the company decided to erect a new and much smaller factory further down Vicarage Lane, more or less where the first buildings were. In 1989, the new building was completed, and over a period of 2 weeks, the entire workforce was transferred. The majority of employees were not very happy with the premises, however, the main complaint being a lack of space. The ground floor had no windows at eye level; so virtually no natural light entered, making it a bit on the dismal side. Also, the Bell pub and Company Clubhouse were a 5 - 10 minute walk away, which rather truncated the lunch hour for those who were partial to a pie and a pint. Nonetheless, the move went smoothly, and the employees settled into their new environment.

In 1990, GEC, in partnership with Siemens, put in a successful bid for Plessey. The company was split between GEC and Siemens, Ilford being taken over by Siemens in October 1990, the company becoming known as Siemens Plessey Defence Systems.

The downfall of the Ilford site may have been due to its reliance on MoD contracts which seemed to "dry up" at the end of the Cold War. The company was looking forward to a contract from the MoD for equipment to replace the British Army's ageing "Clansman" radio system, and with this in mind, plans were made to streamline the new factory and "gear it up" for production of this new system, which went by the name of "Bowman". Unfortunately, the Bowman contract never materialised, and still hasn't to this day (April 2005), and so Siemens Plessey Defence Systems continued to make losses at the Ilford site. This resulted in several periods of redundancies, largely voluntary.

In April 1998, Siemens Plessey Defence Systems was acquired by British Aerospace and became known as British Aerospace Defence Systems. However, this takeover made no noticeable difference to the workload at Ilford, and the site continued to make a loss. In November 1999, British Aerospace merged with Marconi and the company name changed to BAE Systems.

At this time, the total number of employees at Ilford was down to about 200, and it wasn't too long before the decision was made to close the site completely. By the middle of 2001, most of the personnel had gone. Some had taken voluntary redundancy, while the majority had transferred to the Basildon site, with a few going to Rochester.

By the end of 2001, what was left of the Ilford site was put up for sale, and after a couple of years, there were two main contenders. One group wanted a community centre, which seemed to be preferred by the local residents, but finally Crest Nicholson bought the site to build residential homes.

By the middle of 2004, most of the senior managers had left Basildon for one reason or another. Also, some 40 - 50 ex-Ilford people from the Special Projects and Logistic Support departments had been transferred to Great Baddow, near Chelmsford. The Special Projects and Logistic Support departments have now (2005) been transferred to the Italian company Finnmechanica.

The Ilford site was finally demolished in July and August 2004. Vicarage Lane had returned to much as it was in the 1930's.

 Additional material.

Plessey Isle of Wight

To follow.

Plessey Liverpool (Edge Lane)

A history of the Edge Lane site can be found on at  

The Edge Lane site consists of 107 acres of land. In the 19th century, it was a prosperous residential area. Telephone work first started at Edge Lane in 1912 when the Automatic Telephone Manufacturing Company, under Dane Sinclair, took over the already existing works and relevant staff of the British Insulated and Helsby Cable Company (later BICC). In 1925, the Edge Lane plant was enlarged. By 1932, business included automatic traffic lights. In 1936, the ATM Company changed its name to Automatic Telephone and Electric Company (AT&E). In the 50's, the Strowger switching system met competition from the Crossbar system, and production priorities at Edge Lane changed to Crossbar. In 1956, the first Transatlantic telephone cable was set up. In 1961, Plessey merged with AT&E and Ericsson Telephones Ltd, and in 1964, the Strowger Works at Edge Lane became the headquarters of Plessey Telecommunications, controlling the activities of some 30,000 employees worldwide. In 1988, the site became the headquarters of GEC-Plessey Telecommunications (GPT).

After the GEC/Siemens takeover of Plessey and following the loss of the BT 21CN contract and the last-time-buy status of System-X, Marconi (GEC) decided to close the Edge Lane site, making 300 people redundant and transferring 300 to the ex-payphone site at Chorley.

In April 2004, it was announced that the site will be developed jointly by the Liverpool Science Park and the North West Development Agency. The entire Edge Lane site will now be branded under the banner of the Liverpool Science Park. Facilities will include a 'pure' science park and a business park. Once completed, it is envisaged that the Liverpool Science Park will rapidly become the second largest of such developments in the UK, after the Cambridge Science Park, and the third largest in Europe. The Park should create wealth and jobs for Merseyside as well as encourage graduates to stay and create new businesses in Liverpool. (Source:

Plessey Nottingham (Beeston)

This was the original home of Ericsson Telephone. It appears that Marconi (formerly GEC) still have a presence in Beeston, Nottingham. It is not known whether the Marconi site is the same site as Plessey Beeston or merely a part of it.

Plessey Roborough (Plympton, near Plymouth)

Plympton (semiconductors). This site has been shut (confirmation needed!).

Roborough was a state of the art facility and was a huge investment for Plessey (and went considerably over budget). It was opened by Prince Charles who made a derogatory comment about the external appearance looking like a high-tech Victorian prison.

It is not known why it was originally built in Plymouth (maybe because of grants and for increased capacity / product type - CMOS) but the semiconductor plant in Swindon was by then quite old (although subsequently re-fitted as a state of the art bi-polar facility) and expansion there probably wasn’t feasible.

According to a report in the Economist, 13.10.2012, the Roborough site is coming back to life under the Plessey name and CEO Michael LeGoff, a Canadian entrepreneur. Plessey makes now (2012) analogue chips which digitise and process signals such as sound and light, and contracts come from bigger firms. But Michael LeGoff wants Plessey to make its own products and is placing its 2 big bets: the first on its "EPIC" sensor which can detect tiny changes in electrical fields from a distance, and the second on LED's for lighting homes and offices. The revived Plessey is a small outlet with a revenues of £10.5 million in 2011, but it has brand value beyond its scale.

See also notes about the Plessey Swindon site.

Plessey Poole

The Plesey Poole site (Sopers Lane) was a munitions factory during WW2 and site drawings from that time still exist.

It is now (2005) owned and managed by Orb Estates who own Poole Pottery. Siemens leases the buildings back from them. However, Orb Estates went bust in 2004.

Number one building said "Siemens" on it in 2003. It is believed that the telecommunications division was moved out, and merged with Marconi. If so, it was closed with the loss of all jobs in 2001.

No 1 building is still there (2005) but only two of the 3 Floors and the Penthouse are fully in use. A shop is also still in use but the rest of the buildings now contain other businesses including what was Poole Pottery. No 1 building has a structural problem (2005) and its not clear if it can be saved. A while prior to 2005, No 2 building was was used mainly for the rail side of Siemens. In about 2002, most of the old car park was sold off and was replaced by a hotel and some small business units.

Plessey Roke Manor

After acquiring the Roke Manor estate in 1956, the Plessey Company founded Roke Manor Research. Initially staffed by 28 engineers, the company undertook research into military communications systems.

Throughout the 1960s, 70s and 80s, Roke Manor Research grew considerably as the site's reputation attracted key technology contracts in communications and radar. Initially, most of the work was for defence applications but in the mid 1980s work began on ATM (Asynchronous Transfer Mode) switching for the commercial telecommunications market, and GSM cellular telephony.

Following the take-over of Plessey by Siemens and GEC in 1990, Siemens took part-ownership of Roke Manor Research in 1990. In 1991, GEC sold its 50% shareholding in Roke Manor Research and the company became wholly owned by Siemens.

Today (2005), it is recognised as a centre of excellence in the UK for R&D. For further information, see

Plessey Swindon

Plessey is such an important name in the history of Swindon that it is also difficult to overstate its role in the development as the town as we know it today. If we wind the timeline back a century, to 1908, around 80 per cent of men employed in Swindon worked for the Great Western Railway. Swindon's population leapt from 88,000 in 1939 to 104,000 in 1941 as new industries sprang up as part of the war effort, with Shorts, Vickers-Armstrong, Armstrong-Whitworth, Marine Mountings and, most importantly of all, Plessey, now providing employment for ex-railwaymen and a new batch of migrant workers. Plessey, known then primarily as a manufacturer of radio components, opened its factory in Kembrey Street, Gorse Hill, in 1940.

By 1952, when some items were still rationed, the Town Development Act had sealed Swindon's future, with Plessey playing a leading role. The Act led to the building of Cheney Manor Trading Estate which was to become the heart of the ever expanding and diversifying Plessey operation as the company chose the estate as the site of its new factories. The workforce had expanded to 2,300 by the mid-1950s, and by 1960 an incredible turnaround was complete, with Plessey supplanting the railway factory as Swindon's leading employer.

By the beginning of the 1960s the ranks of Plessey workers in Swindon had swelled to more than 5,000, but more expansion was to come with the opening of another Cheney Manor factory in 1962, providing a further 350 jobs in resistors. There were now three Cheney Manor sites - called Building 101, Building 102 and Building 103 - as well as the original and now substantial factory at Kembrey Street, which covered roughly the area of two football pitches.

The company encouraged sport and had a suitably impressive private sports ground in Ermin Street at Stratton St Margaret. A social club in Gorse Hill was a popular venue for those who weren't necessarily so active. For years after Plessey closed, the social club was called the ex-Plessey Club and was to be one of the most persistent reminders of its former glory after the firm's importance as an employer declined.

Zarlink Semiconductor, which acquired GEC-Plessey Semiconductors in 1998, was originally part of Mitel, the Canadian corporation. In 2005, it ran a design centre, sales office and manufacturing facility at Plessey's original factory in Cheney Manor, employing around 400 people in Swindon. In 2008, the site was sold by Zarlink to privately owned MHS Industries; there were only 120 staff remaining  in March 2008). It was the demise (bankruptcy) of the UK element of MHS that prompted a management buyout of Swindon & Roborough (called Plus-Semi) and the revival of the Plessey Semiconductor name in 2009.

See for a more comprehensive history of the Plessey Swindon site.

Plessey Titchfield

This site is still in existence today albeit not Plessey. In 1977, the site was Plessey Wound Components and Plessey Aerospace, with well over 1200 employees. Since then the components side of the site was sold in 1980 leaving just the Aerospace business. It was sold at an unknown date to Cobham under the name of FR-HiTemp Limited. In 2005, there were fewer than 600 employees at the site. The site occupied in 2006 well under half of the ground that it once did after the GEC/BAE/Cobham takeovers and much of the land was sold off. At the end of 2006 Cobham sold the site to the US firm Eaton Corporation. The site is now re-named Eaton Aerospace Limited and carries on the manufacture of the same Plessey products and a few new ones as well, just under a different name. However many of the buildings that still exist today remain unchanged. In fact, someone returning to the site after 30 years would instantly recognise it now as it was then. Many of the Aerospace products that were manufactured back in the Plessey days are still made today. In fact some still have the old Plessey logo on them when they are returned for repair! Indeed some of the customers today still recognise the name Plessey better than the one currently used. Many present employees still recall memories and stories of the good old Plessey days. This seems to be a feeling across many former Plessey sites.

Plessey West Leigh (Havant)

It is believed that the site has been redeveloped for housing.

General notes re Plessey sites and staff:

A company called Orbitel was set up in the early 90s in Basingstoke to design mobile phones. It was partly owned by Plessey (by now GEC/Siemens), and was full of ex Plessey people. Orbitel was eventually sold to Ericsson, who also acquired Vodafone's part share holding, and enjoyed great success until 2001, when a series of staff reductions and cutbacks began. It is still (2003) trading in Basingstoke as Ericsson Mobile Platforms.

The Plessey name still survives (2005) - along with the distinctive wave logo - in a South African company. It's the country leading telecommunications company.

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