Words for Battle (aka by its original title In England Now) is a British propaganda film produced by the Ministry of Information's Crown Film Unit in 1941.
 It was written and directed by Humphrey Jennings, and features seven sequences, each containing images of rural and urban Britain at war overlaid with audio commentary by Laurence Olivier, reciting passages from different English literary works and speeches.
London Can Take It!
 is a short British propaganda film from 1940, which shows the effects of eighteen hours of the German blitz on London and its people.
 Intended to sway the US population in favour of Britain's plight, it was produced by the GPO Film Unit for the British Ministry of Information and distributed throughout the United States by Warner Bros..
 The film was directed by Humphrey Jennings and Harry Watt, and narrated by US war correspondent Quentin Reynolds.
An Airman's Letter to His Mother (1941) is a documentary-style British propaganda short film based on an actual letter from a British bomber pilot to his mother published in "The Times" in June 1940.
 Subsequently, the letter was published as a pamphlet and received wide distribution in the UK.
 "The letter in question had touched a nation's heart and made a popular film subject."
 In 1941, Michael Powell directed "An Airman's Letter to His Mother", based on a dramatization of the letter, and narrated by John Gielgud.
Builders is a 1942 British propaganda film, which outlines the importance of the work of builders during the Second World War.
 It was produced by Ian Dalrymple at the Crown Film Unit of the Ministry of Information, and directed by Pat Jackson.
Listen to Britain is a 1942 British propaganda short film by Humphrey Jennings and Stewart McAllister.
 The film was produced during World War II by the Crown Film Unit, an organisation within the British Government's Ministry of Information to support the Allied war effort.
 The film was nominated for the inaugural Academy Award for Documentary Feature in 1943, but lost against four other Allied propaganda films.
 It is noted for its nonlinear structure and its use of sound.
Red Chinese Battle Plan is a 28-minute black-and-white propaganda short produced by the United States Department of Defense in 1967.
 Presented as a documentary film on Chinese history to military servicemen, the propaganda short describes the People's Republic of China as plotting to "conquer and enslave" the world.
Stewart McAllister (27 December 1914 – 27 November 1962) was a British documentary film editor who collaborated closely with Humphrey Jennings during the Second World War to produce films for the Crown Film Unit of the Ministry of Information.
 His contributions towards these films was largely neglected until Dai Vaughan's biography of him, "Portrait of an Invisible Man", was published in 1983.
A Summer in the Cage is a 2007 documentary film about a man's experiences with bipolar disorder.
 The film follows the filmmaker's friend Sam and features an interview with mental health scholar Kay Redfield Jamison.
 It was directed by Benjamin Selkow.
 The documentary debuted on the Sundance Channel in 2007.
A Defeated People is a 1946 British documentary short film made by the Crown Film Unit, directed by Humphrey Jennings and narrated by William Hartnell.
 The film depicts the shattered state of Germany, both physically and as a society, in the immediate aftermath of World War II.
 The narration explains what is being done – and what needs to be done – both by the occupying Allied forces and the German people themselves to build a better Germany from the ruins.
The Silent Village is a 1943 British propaganda short film in the form of a drama documentary, made by the Crown Film Unit and directed by Humphrey Jennings.
 The film was named one of the top 5 documentaries of 1943 by the National Board of Review.
 It was inspired by the Lidice massacre in Czech Republic in June 1942.

Question: What is a 1942 British propaganda short film by Humphrey Jennings and Stewart McAllister , A Summer in the Cage or Listen to Britain ?
Answer: Listen to Britain