Dominated by Alec Guinness’ enormous toothy grin, this is an all-time classic Ealing Studios comedy.

In a delightfully eccentric plot, Guinness plays the seedy and sinister Professor Marcus, the leader of a disparate bunch of crooks who take up residence in little old Katie Johnson’s boarding house.

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

Cecil Parker is the Major, Peter Sellers wears a teddy boy outfit, Herbert Lom is Louis the pyschopath, Danny Green seizes his best chance from a career of bit parts – 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 extremely funny with a perfect ending.