A suburban police station is understaffed due to a flu epidemic, and Sergeant Wilkins, under pressure to maintain staffing levels, is pleased to hear that three new recruits, fresh out of training school, are due shortly.
On their way into the station, the three policemen inadvertently assist some bank robbers into their getaway car, and are embarrassed when they learn the truth. The new constables are self-proclaimed intellectual and amateur psychologist PC Timothy Benson, former socially well-connected playboy and cad PC Tom Potter, and extremely superstitious PC Charles Constable. The arrival of WPC Gloria Passworthy, with whom Constable falls in love, and Special Constable Gorse completes the roster.
Out on the beat, the new constables try hard, but are less than successful. Benson nearly arrests a plainclothes detective, and Constable believes he has heard a murder being committed, but it turns out to be a radio play. Potter investigates a report of an intruder, but finds a young woman in the bath and engages in a civil conversation with her about her recently broken relationship. Gorse, tasked to patrol with a police dog, is unable to control it. With their careers on the line, they double down and have better luck when a wages robbery takes place. Benson and Potter locate the getaway car, and all four engage in a confrontation with the thieves, arresting them and recovering the money.
Commended for his efficiency and excellent results, Inspector Mills is promoted to a training position and Wilkins is promoted to replace him. Charlie Constable gets his girl (with a little help from Sgt. Moon) and stops being superstitious.
Sid James as Sergeant Frank Wilkins
Eric Barker as Inspector Mills
Kenneth Connor as Constable Charlie Constable
Charles Hawtrey as Special Constable Timothy Gorse
Kenneth Williams as PC Stanley Benson
Leslie Phillips as PC Tom Potter
Joan Sims as WPC Gloria Passworthy
Hattie Jacques as Sergeant Laura Moon
Shirley Eaton as Sally Barry
Cyril Chamberlain as PC Thurston
Joan Hickson as Mrs May
Irene Handl as Distraught Mother
Terence Longdon as Herbert Hall
Jill Adams as WPC Harrison
Freddie Mills as Jewel thief
Brian Oulton as Store manager
Victor Maddern as Detective Sergeant Liddell
Esma Cannon as Deaf old lady
Hilda Fenemore as Agitated woman
Lucy Griffiths as Miss Horton
Noel Dyson as Vague woman
Dorinda Stevens as Young Woman
the fourth in the series of 31 Carry On films (1958–1992)
Sid James makes his debut in the series here
It was the first "Carry On..." film to include some nudity with Connor, Hawtrey, Williams, and Phillips baring their behinds during a shower scene.