In my younger days in the '60's/70's I used to prefer this film over The Belles Of St. Trinian's, Alistair Sim's other schoolmasterpiece from 4 years later. Happiest Days has the delicious meeting between the unflappable Sim and the indomitable Margaret Rutherford while Trinians had the unrepeatable meeting between Sim and Sim. Also this story didn't have such a broad canvas and watching it tonight for the first time in 20 years and finding I remembered perfectly every line and every image made me realise it's gone deeper than I thought. Simpler is often more effective, is that how come it appears so short? A lot of half-baked and over-baked ideas were thrown into this brief 80 minute mix.

Boys school run by Sim and his band of bachelors is physically invaded by girls school run by Rutherford and her set of spinsters thanks a series of lackadaisical mistakes at the Ministry Of Inboxes (still in existence) and they all have to try and make do and mend. The main comedy is in adjusting to the novelty of the situation and trying to maintain the pretence that there was only one school in the building to the various visitors to both schools descending at the same time. Sly jokes fall thick and fast delivered by an expert slapstick cast, sardonic Richard Wattis – who went on later to Trinians and Sykes, ladykiller Guy Middleton, fluffy Arthur Howard – who went on to Jimmy Edwards' Whack-O as Mr Pettigrew, and flighty Joyce Grenfell. But it's the sparking, the verbal sparring of Sim and Rutherford in every scene they're in that's so wonderful to behold and is the big reason for watching the film.

The time has now gone, the Britain this shows was murdered decades ago. For instance we now live in a world where the two Guard Thine Honour jokes in here will be meaningless to most or if understood probably treated with contempt by most of the rest. But recommended by this simple guy for a laugh and a sigh.