Lots of American stars popped up in British B movies of the early 1950s - this has George Raft, looking old but he's still George Raft, as a man trying to find out who is abducting British nuclear scientists.
There's a great scene where a girl, Sally Gray, beats up Raft - she gets a gun off him and everything. Poor George! In another scene he's wearing a frilly apron in the kitchen. But don't worry, Raft fans, George gets to take over the action and gets the girl even though he's old enough to be her grandfather.
It's a weird sort of movie - Raft feels slightly out of place, and the genres mix uneasily (detective/Cold War spy/British setting). It moves fast, there's some good acting and location work in London.