Alastair Sim is tragically remembered today for only one role: he was without any question the definitive Ebenezer Scrooge, and usually the only film that anyone today has seen featuring Sim is his 1951 turn in A CHRISTMAS CAROL. In fact, Sim starred in a wide range of comedic and dramatic roles in the 1940s and 1950s. He was a familiar enough presence that Alec Guinness paid homage to him by doing a straightforward imitation of Sim in the 1955 film THE LADYKILLERS, evening wearing false teeth to look more like Sim.
Sim managed to play in a large number of comedic suspense and mystery films. He starred in a series of Inspector Hornleigh films in the early forties, he went on to play memorable roles in wartime mysteries such as COTTAGE TO LET (with a very young John Mills in a key role), GREEN FOR DANGER, AN INSPECTOR CALLS (in which he plays a ghostly police inspector), and THE GREEN MAN, in which Sim plays a congenial assassin. But Sim also excelled in pure farce, and was magnificent in such films as THE HAPPIEST DAYS OF YOUR LIFE, LAUGHTER IN PARADISE, and the St. Trinian movies, which he played largely in drag. Sim, with his large frame, lugubrious eyes, and marvelously dramatic voice, was a delight in every film he graced, but today is primarily known for Scrooge, as noted above.
There is actually a very good historical reason for the demise of Sim's reputation and of British cinema in general. In the fifties and sixties, French auteur criticism came more and more to dominate European and American film criticism. One of the central assumptions of auteur critics has been that British cinema, with the almost exclusive exception of pre-Hollywood Hitchcock and the workd of Michael Powell and Eric Pressburger, has been an aesthetic wasteland. As an ardent fan of forties and fifties British cinema, I know that this is an utterly false representation of what was actually happening in England. There were a number of excellent directors and a large number of superb actors and actresses who somehow or other were not siphoned off by Hollywood.
GREEN FOR DANGER is one of Sim's finest films. The plot is largely superfluous. A postman dies in an operation in WW II England, under shady circumstances, and the great Inspector Cockrill is called in to solve the mystery. The movie is entirely a showcase for Sim's eccentric histrionics. The movie sinks or swims entirely on how one responds to Sim: if you love him (as I do), you will love this movie. If you dislike Sim (I reaction that would utterly mystify me), you will dislike this film.
I strongly urge all lovers of film comedy to search this film out. I especially recommend this to lovers of British cinema. I will add that I believe this to be the best film that Alastair Sim ever made, though I would hasten to add that he made a dozen others very nearly as good. They are large hard to find these days, but searching them out will definitely repay the effort.