| Director | Mario Zampi |
|---|---|
| Box office | £133,313 |
George Potts, a plumber in a top secret government research plant, accidentally comes into possession of the plans for a revolutionary atomic weapon. As George leaves for his annual holiday, the research security team embarks on a nationwide search for the hapless 'sanitary engineer'. Meanwhile, the Russians get wind of the incident and intercept George, plying him with liquor and employment promises so that he'll hand over the plans to them. All the while, George never knows what the fuss is about: he thinks that the British and Soviet authorities are interested in his new plans for a modern ballcock system he is carrying. The Russians offer him a job in the Kremlin doing research (on plumbing, he believes), and steal his ballcock plans.
They put George in prison and interrogate him, using a truth drug, but although he tells them truthfully that he hid the plans in the lining of Tania's coat, they have disappeared, because they are in Zekov's coat lining.
While there he falls in love with secret agent Tania, and discovers the true nature of the plans he is carrying.
George organises a flight to East Berlin where Zekov is waiting, unaware that he is carrying the plans.