Green for Danger is a 1946 British thriller film, based on the 1944 detective novel of the same name by Christianna Brand.

It was directed by Sidney Gilliat and stars Sally Gray, Trevor Howard, Rosamund John, Leo Genn, and Alastair Sim.

Inspector Cockrill is typing a report to his chief at Scotland Yard on the "amazing events" beginning on 17th August 1944, with postman Joseph Higgins "the first to die".

Mr. Eden commiserates with Nurse Sanson about the nightmares she has had since the death of her mother, suggesting the work with bombing victims is a reminder.

Leaving the party, she goes through the windy night to the operating theatre to retrieve her proof and is met by a gowned and masked figure holding a scalpel.

Cockrill scratches black paint off the original "oxygen" bottle, revealing the green surface signalling carbon dioxide.

He reveals that he was trying to give her the antidote to the poison tablets (although instead of communicating this to the others, he locked himself and Sanson in the other room, making everyone think he was up to no good).

She thought of turning this into a thriller but could not think of a motive until a drunk man told her of an experience in a bomb shelter.

Though not attracted by the detective or the hospital setting, he said, "what appealed to me was the anaesthetics - the rhythmic ritual, from wheeling the patient out to putting him out and keeping him out (in this case, permanently), with all those crosscutting opportunities offered by flowmeters, hissing gas, cylinders, palpitating rubber bags, and all the other trappings, in the middle of the Blitz, too.

"[6] In December 1945, the film was announced as a project for Individual Pictures, the company of Gilliat and Frank Launder.

[6] According to trade papers, the film was a "notable box office attraction" at British cinemas in 1947.

[14]) The Monthly Film Bulletin said: "Though the story has plenty of improbabilities when considered in cold blood, this thriller holds one well when on the screen.

Alastair Sim is most amusing as the self-important detective who enjoys tormenting his suspects, but who comes a partial cropper despite his assurance.

"[15] Leslie Halliwell noted that it was a "classic comedy-thriller, with serious detection balanced by excellent jokes and performances, also by moments of fright".

[17] The New York Times stated: "Sidney Gilliat and Frank Launder have laid deftly humorous hands on the subject of murder.

And, while they manage to keep the spectator chuckling most of the time, they never for a moment lose sight of a mystery film's prime purpose—that is, to intrigue and startle the onlooker.

In the case of Green For Danger one could reasonably request just a bit more justification for the solution, which, truth to tell, is bewildering.

"[18] The Brooklyn Eagle was enthusiastic and praised the film as "an expert concoction of thrills, homicide, and laughs.

It's also a fine showcase for the talents of Alastair Sim, a new type of detective with a sense of humor.

"[19] For the Buffalo Courier-Express, the film was "an ambitious, highly acceptable murder melodrama...expertly acted and smartly directed....the musical score is a big asset.

"[20] The Criterion Collection released Green for Danger on laserdisc in 1993, with optional audio commentary by Bruce Eder.

The DVD also includes a booklet with an essay on the film by Geoffrey O'Brien and a programme note by Gilliat from a 1960s revival screening.