When Professor Willingdon becomes wary of the nuclear weapons he is helping build, he steals a warhead and threatens to detonate it in London in seven days unless the government begins nuclear disarmament. As Willingdon goes into hiding, Detective Folland of Scotland Yard sets out to find him. Willingdon's daughter Ann also joins the cause, hoping she can talk sense into her father before he causes a catastrophe.
Barry Jones
as Professor John Malcolm Francis Willingdon
André Morell
as Superintendent G.W. Folland
Olive Sloane
as Goldie Phillips
Sheila Manahan
as Ann Willingdon
Hugh Cross
as Stephen Lane
Joan Hickson
as Mrs. Emily Georgina Peckett
Ronald Adam
as Arthur Lytton, the Prime Minister
Marie Ney
as Mrs. Willingdon
Joss Ackland
as Station Policeman
Marianne Stone
as Woman in Phone Box
John Stratton
as Army Mechanic
