Compelled (1960) British crime b-movie, with Ronald Howard, Beth Rogan & John Gabriel.
Engineer, and ex-con, Paul Adams, has an unexpected visit from Fenton, a villain from his past.
Fenton, a habitual criminal, has plans to burgle a local jeweller's, by building a tunnel between the basement of a bookshop he owns, and the vault of the jeweller's shop, but needs to make sure that the tunnel will be safe and secure enough to do the job.
This is where Adams comes in. Fenton has knowledge of Adams' 2-year stretch for drugs, which, up until now, Adams has kept as a secret from his wife and boss.
Knowing this, Fenton uses the "threat to tell all" line to convince Adams to help him with the heist.
First off... the picture quality isn't the best. Plus, this isn't the greatest British crime b-movie out there, but is a fairly decent Danziger effort.