The fourth Carry On is marked by the debut of Sid James who went onto become a regular cast member although he wasn't the first choice for this film. It was also the last that featured Leslie Philips who had been in the previous two. The police was the obvious next subject after the scriptwriters had tackled National Service, the NHS and Education. In many ways this is a weaker film than the first three, following the structure of the films to date and the main actors playing very similar roles to what they had already done. But it's still a neat and funny British comedy and manages to show what the police force, with its discipline, beat work and strict etiquette was actually like. A huge flu epidemic has caused a shortage of officers to patrol so three raw recruits (Kenneth Williams - a brainy nerd, Kenneth Connor - a superstitious man and Leslie Philips - a posh one) are drafted in to fill the ranks. They are helped by a Special Constable (Charles Hawtrey) and between them manage to get everything wrong in a series of episodic sketch type scenes. James is the harassed Station Sergeant trying to manage them while dealing with the busybody Inspector (Eric Barker). The usual cast are along for the ride including Joan Sims, Hattie Jacques and Shirley Eaton (with a bit of risqué nudity). Like the early films in the series this is comedy anchored in the real world and has that nostalgia for the times. It's an example of classic British comedy and well worth seeking out.