[1] The screenplay was by Hughes and James Eastwood, based on the 1953 BBC Television series of the same name written by Eric Maschwitz.

[2] Detectives from Scotland Yard investigate a series of murders of leading nuclear scientists, and are intrigued by strange reports received about the crimes.

After its success the company began making more expensive productions, often hiring American stars for international appeal.

[8] Variety wrote: “Like many British-produced pictures, it lacks American-type pace and is a routine entry in the program market.

... Hughes keeps the action on the boil, while Russell Napier and Rona Anderson are fine as a Scotland Yard detective and his niece.