Somebody's attempt to make "noir" films in England. The Gambler (from the States) is doing all right in England with his clubs and his fighters and his horses, but he craves the society and acceptance of British nobility, who he foolishly imagines to be from a better class than himself. This is how he meets The Lady.
Stir all this up, throw in a jilted showgirl and the menace of Italian muscle moving in, and you've got yourself a movie. Of sorts. Some humour and clever writing, but overall stiff and improbable.