Dominated by Alec Guinness’ enormous toothy grin, this deliberately eccentric comedy shows Ealing Studios’ at the top of its game.

Guinness plays Professor Marcus, the leader of a disparate bunch of crooks who take up residence in mild-mannered little old lady Katie Johnson’s boarding house.

They pretend to be a string quintet and then, instead of murdering her as planned, they end up trying to kill each other.

Cecil Parker is the Major, Peter Sellers wears a teddy boy outfit, Herbert Lom is Louis the psychopath and there’s even an encounter with a young Frankie Howerd.

The soft colours and real London locations make it great to look at and, most importantly, it is very funny – the perfect ending is a jewel in the crown of British film comedy.