Seven Days to Noon (also known as Ultimatum) is a 1950 British political thriller film directed and produced by John and Roy Boulting and starring Barry Jones, Olive Sloane and André Morell.

[1] It was written by Frank Harvey and Roy Boulting based on a story by Paul Dehn and James Bernard.

The letter is signed "Professor Willingdon", which is the name of the senior researcher at Britain's atomic weapons development facility, the fictitious Wallingford Research Centre, so, on Monday, Detective Superintendent Folland of Scotland Yard's Special Branch is charged with investigating whether the letter is a fraud or represents a genuine threat.

At the Research Centre, Folland finds that Willingdon has gone missing, as has a (fictitious) UR12 nuclear bomb, which is small enough and light enough for an individual to carry.

Neither Lane, nor Willingdon's wife or daughter, Ann, had noticed anything unusual in the Professor's recent behavior, but troubling notes are found among his papers which, coupled with some remarks he made to the local vicar, who is the last person known to have spoken with Willingdon, indicate he had come to believe that his life's work was being used by the government for evil purposes.

On Tuesday, Willingdon, who is carrying the bomb around with him in a Gladstone bag, sees his picture in the newspaper (though it is not stated why he is wanted), so he has a barber shave off his moustache before looking for a place to stay.

By Thursday, rumours of war are circulating and there is a growing crowd outside 10 Downing Street, so the Prime Minister decides to finally make a statement over the radio.

When she gets home, she finds Willingdon waiting for her—the ever-intensifying search has made him nervous, so he has decided to hold Goldie hostage in her apartment, saying he will blow up the bomb prematurely if she calls for help.

Goldie, who is on Westminster Bridge attempting to hitch a ride to Aldershot hears the all-clear sirens and heads for home.

"[12] Monthly Film Bulletin wrote: "Seven Days to Noon is a first class thriller with a theme of alarming topicality.

"[13] In The Spectator Virginia Graham said: "Mr Barry Jones and Miss Olive Sloane give outstanding performances, the script is both witty and wise, and if, perhaps, the London Police do not emerge with flying colours, flags can be run up for all other participants in this giant game of hide and seek".