It is a satire on British industrial life in the 1950s. The trade unions, workers, and bosses are all seen to be incompetent or corrupt to varying degrees. The film is one of a number of satires made by the Boulting Brothers between 1956 and 1963. Curiously, some trade unionists have rather enjoyed it in an ironic way, since the shop steward Fred Kite is the most interesting character, and it was one of the few films of that time to deal even halfway seriously with trade unionism and factory life.
At first suspicious of the overeager newcomer, Communism-admiring shop steward Fred Kite (Peter Sellers) takes Stanley under his wing and even offers to take him on as a lodger. When Kite's curvaceous daughter Cynthia (Liz Fraser) drops by, Stanley readily accepts.
Meanwhile, personnel manager Major Hitchcock (Terry-Thomas) is assigned a time and motion study expert, Waters (John Le Mesurier), to measure how efficient the employees are. The workers refuse to cooperate, but Waters tricks Windrush into showing him how much more quickly he can do his job than other, more experienced employees. When Kite is informed of the results, he calls a company-wide strike to protect the rates his union workers are being paid.
This turns out be exactly what Cox and Tracepurcel want. Cox owns a company that can take over a large new contract with a Middle Eastern country, at an inflated cost. He, Tracepurcel, and Mr. Mohammed (Marne Maitland), the country's representative, would each pocket a third of the £100,000 difference.
However, things don't work out the way either side wants. The press reports that Kite is punishing Windrush for working hard. When Windrush decides to cross the picket line and go back to work (and reveals his connection with the owner of the company), Kite asks him to leave his house, provoking Kite's wife (Irene Handl) and daughter (who likes Stanley very much) to call their own private strike. Meanwhile, Cox's workers leave their jobs in sympathy. More strikes spring up, bringing the country to a standstill.
Faced with the new developments, Tracepurcel has no choice but to send Hitchcock to negotiate with Kite. They reach an agreement, but Windrush has made both sides look bad and has to go. Cox tries to bribe him with a bagful of money to resign quietly, but Windrush turns him down. On a televised discussion programme moderated by Malcolm Muggeridge (playing himself), Windrush reveals to the nation the underhanded motivations of all concerned. When he throws Cox's bribe money into the air, the studio audience riots. In the end, Windrush is convicted of causing a disturbance and everyone else is exonerated. He is last seen with his father relaxing at a nudist centre.