Surprisingly tough, given that this was made in 1963, and surprisingly good British crime movie directed by the usually reliable Ken Annakin. It's based on the novel, "Death of a Snout" and it's about Police Inspector Nigel Patrick's attempt to find out who killed his number one informant. It has an excellent cast that includes Margaret Whiting, Darren Nesbitt, Frank Finlay, Roy Kinnear, Harry Andrews and Colin Blakely and Annakin makes great use of his London locations. It may not surface very often these days but it's certainly worth seeing.