A disgraced school master, Benjamin Twist, is mistaken for a tough prison governor and assigned the charge of a prison for particularly hardened criminals. Believing he is being sent to a school rather than a prison, he celebrates accordingly only to find that his drunkenness accidently lands him on the wrong side of the prison bars. The Governorship is eventually restored to him, and he sets about popularising himself amongst the convicts by turning a blind eye to their shady dealings.
When it turns out that "Twist" (Will Hay) is no good as an headmaster he is turfed out and looking for a new job! An administrative mix up sees him appointed the governor a prison, and after another which sees him temporarily behind the bars, he tries to ingratiate himself with the prisoners and, predictably, they run rings round him as he is soon well out of his depth. Will Hay had good comedy timing and together with a decent cast of regulars manages to raise a laugh or two, but the film is way too long and the joke doesn't really sustain it for ninety minutes. That said, though, it is still quite watchable, if only to remind us was made us laugh in the simpler, less cynical days before the second world war.