In the dramatic British thriller Seven Days to Noon (1950), what did the disturbed scientist threaten to do?

Answer 1

Destroy London with a nuclear bomb

Idealistic and unhinged Professor Willingdon (Barry Jones), an employee at the Wallingford Research Centre which developed atomic weapons, stole a nuclear warhead and threatened to detonate it in one week's time (at noon) if the government didn't outlaw nuclear weapons.