As the Earth heats up, Bill McGuire asks for information on the melting point of "everything from steel to my glass eye". Leo McKern did in fact have a glass eye.

Towards the end, Stenning is driving to Genie's apartment, when he stops to talk to a policeman, who is played by Michael Caine, in an early role.

The realistic newspaper footage, was shot in the Fleet Street offices of Express Newspapers, and gives a vivid picture of the "old" London Fleet Street industry (most British newspapers have now moved out of this area, which was famous as a press center). "Express" Editor Arthur Christiansen plays himself in the film.

In an early scene Jeannie is struggling with a Roneo stencil duplicator, saying it is "over-inking". The Roneo company threatened to sue the producers for the potential damage to the reputation of their products.

The scenes of the "Met Office" were filmed both outside and inside the Ministry of Defence main building in Whitehall. This access was remarkable. Those interiors were little changed, until refurbishment after 2000.

Editor James Needs used stock footage from Hammer's The Quatermass Xperiment (1955), also directed by Val Guest, of a fire truck racing through the night past the patrol station in Bray.

The film received an "X" certificate from the British Board of Film Censors upon release in 1961, barring anyone under sixteen from seeing it.

In the early 1990s Val Guest was attached to a mooted remake, to be set in New York City, though the plans fell ultimately through.

At around 1:30, near the end of the movie, Bill Maguire quotes the first two lines of the 1826 poem "Casabianca" by British poet Felicia Dorothea Hemans: "The boy stood on the burning deck/Whence all but he had fled".

Bill Maguire quotes Dante Alighieri's poem "Divine Comedy": "Abandon all hope, ye who enter here."

At the beginning of the film, Peter Blythe makes a brief uncredited appearance as the copy desk boy taking 'Stenning's' story, and Leo McKern also stars as science reporter 'Bill Maguire'. Twenty years later, they would both star together in the hit television series Rumpole of the Bailey (1978), with McKern in the title role and Blythe as Head of Chambers, Sam Ballard.

Edward Judd receives 'and introducing' credit.

One of the final shots shows the print room with two copies of the newspaper pinned up. One saying " World Saved", the other saying "World Doomed". It remains unsaid which version they will print.

Saturday Review magazine cover story, issue date February 10, 1962. Review by Hollis Alpert.

Opening credits: The events and characters depicted in this photoplay are fictitious. Any similarity to actual persons, living or dead, is purely coincidental.