Carry On Constable has distinct shades of the first film in the series, Carry On Sergeant, in that a bunch of hapless, hopeless new recruits need to be pulled into shape by a world-weary, put-upon Sergeant. In this case (as the title suggests) it's the police force rather than the army that provides the setting from which the old jokes get launched.
However, Constable really marks a turning point in the (at the time) fledgeling series. This fourth outing marks the first time where the stereotypical characters are so obviously present - Charles Hawtrey reprises his Private Golightly role as the effeminate, harmless SPC Gorse, Kenneth Williams' Constable Benson is the slightly camp, very superior intellectual that he played in all three of the previous outings, Leslie Phillips is the womanising loafer that blessed Carry On Nurse so well, and Hattie Jacques manages to show a little humanity in the soul of the 'matronly' role of Sergeant Moon.
The other key element in Constable, of course, is that it marked the first appearance of Sid James. As Sergeant Wilkins, it's his job to be frustrated by the ineptitude of his recruits, and confounded by the attentions of his superior (once again played by the great Eric Barker).
It's pretty standard early Carry On fare - you know there's going to be some catastrophies, you know there's going to be a successful ending, and you know more than anything that there's going to be some sort of drag act somewhere in the plot. But that's fine, because that's really what Carry On is generally all about - the comfort of knowing that you're visiting a well-loved family member, and your visit will entertain and satisfy. Carry On's are the comfort-food of the British film-viewing public: they know what's on offer, and they know they will enjoy it. Constable is no different - it does exactly what it says on the DVD box......