3 Steps to the Gallows (1953) on Netflix

Plot summary

Gregor Stevens is an officer on an American merchant ship, and when he comes ashore in London he goes looking for his brother Larry. He learns instead that Larry has been convicted of murder and has three days left before he is hanged. Gregor sets out to clear him, and his search leads him to an organized smuggling gang that works out of a nightclub. There he meets Yvonne Durante, an entertainer who also smuggles on the side. She agrees to help him, though the diamond-smuggling confederates she works with are dangerous company and her part in it puts her at risk.