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Coleshill Auxiliary Unit bunker, Oxfordshire

A rare surviving bunker used by the unit set up to be the British Resistance if the Nazis had invaded the UK.

The Coleshill estate lies in countryside near the small town of Highworth, which though now in Oxfordshire was part of Berkshire during WW2. Like many country estates in WW2 it was requisitioned for use by the Government, though unlike some others its activities were clandestine. It played host to a factory making VHF radios for undercover operations, and the training centre for the auxiliary units, a secret organisation set up to form the British Resistance in the event of a German invasion of the UK. After the war it was given to the National Trust, and though the house was destroyed in an unfortunate fire in 1953 it has been run by them ever since.

The subject of this report is one of the bunkers that was used to train the auxiliary units and which served as the blueprint for all the other auxiliary unit bunkers built around the country. It lies in a patch of woodland and is a small underground chamber made from corrugated iron, brick and concrete with an entrance hatchway and ladder behind a blast wall at one end and an escape tunnel at the other end. In addition it had two small alcoves, one for storage and one for a chemical toilet, and a concealed flue for a cooking stove.`

Today the escape tunnel which used to emerge in a bank a short distance away has collapsed, and the National Trust have created a new entrance with a locked gate in the void it leaves. The original entrance which would once have been covered by a camouflaged trapdoor has been replaced by the trust in a similar fashion with a locked manhole cover. A dead tree set in concrete which once concealed the cooking stove flue has long since rotted away leaving only a few pieces of concrete in the leaf litter. This location does not have the antenna wire concealed in the bark of a nearby tree that is a feature of so many other auxiliary unit sites.

This site visit was as part of an official guided walking tour of the WW2 history of the Coleshill estate in the company of several National Trust members and in the capable hands of a National Trust historian, for whose informed commentary I was very grateful.

To the bunker itself, here's the view that would have met a trainee entering through the hatch. The ladder is original and is made from an old piece of estate fencing. The hatch would originally have had a sliding mechanism with a counterweight, and would have incorporated a concealed mechanism for opening it from the outside. At the bottom of the ladder can be seen the blast wall with a narrow opening to the left.

Once inside, looking back towards the hatch we see the other blast wall. The chemical toilet would have been behind the doorway on the left and the cooking stove was opposite it.

Looking towards the escape tunnel the modern day entrance can be seen. On the right through the doorway is a storage alcove. Originally there would have been a wooden floor, however in the seven decades since the war it has rotted away. The bunker is designed to drain itself with any water finding its way through the hatch following the channel down the centre of the floor and flowing away through the escape tunnel. Later auxiliary unit bunkers had escape tunnels made from concrete pipe sections, this one was made from corrugated iron.

On the left in the above photograph you can just see the remains of one of the bed frames used by the trainees. This would have been suspended from the wall on brackets when needed. A closer look at the bed frame is below.

Coming away from the bunker there is little surface evidence remaining of Coleshill's WW2 activity, something which perhaps befits its clandestine status. There are a few mossy concrete building bases where the radio factory once stood and a few depressions in the ground where the auxiliary units once learned to man observation posts or hide their ammunition but other than that the only WW2 structure of note is the former guard house standing incongruously next to the kitchen garden.

The 1953 fire that destroyed the house has probably saved what little WW2 structures remain, by ensuring that the estate has remained a neglected agricultural backwater rather than being given one of the overdone country house makeovers for which the trust has in the past become infamous.

This site is not open to the public, it is a fragile heritage site kept securely locked and people are not encouraged to visit it. For that reason I am not giving any details of its exact location. Happily though the National Trust do run guided tours from time to time and if you wish to find out when the next one is then I suggest you do what I did and ask nicely at the Coleshill and Buscot estate office.