The GPO Film Unit was a subdivision of the UK General Post Office.
Headed by John Grierson,[1] it was set up to produce sponsored documentary films mainly related to the activities of the GPO.
Among the films it produced were Harry Watt's and Basil Wright's Night Mail (1936), featuring music by Benjamin Britten and poetry by W. H. Auden, which is the best known.
Directors who worked for the unit included Humphrey Jennings, Alberto Cavalcanti, Paul Rotha, Stuart Legg, Harry Watt, Basil Wright and a young Norman McLaren.
A second volume, We Live in Two Worlds was released in February 2009, with 22 films covering the period 1936 to 1938, and includes Night Mail.