Despite the fact that the film is set in 1950s Birmingham, there's not a trace of a Brummie accent from a single character. The cast manage "educated RP'" cockney and estuary English--all from London and the South East of England.
Three years earlier in Seven Days to Noon (1950), Victor Maddern had played the role of the soldier who shoots the mad bomber. However here, in a reversal of sorts, Maddern plays the part of the mad bomber.
Peter Lyncort (Glenn Ford) is mentioned as having been born in Quebec, Canada. Ford was actually born in Quebec, Canada.
Finnish visa # 41306 delivered on 19-10-1954.