Night Mail is a 1936 British documentary film directed and produced by Harry Watt and Basil Wright, and produced by the General Post Office (GPO) film unit. The 24-minute film documents the nightly postal train operated by the London, Midland and Scottish Railway (LMS) from London to Glasgow and the staff who operate it. Narrated by John Grierson and Stuart Legg, the film ends with a "verse commentary" written by W. H. Auden to score by composer Benjamin Britten. The locomotive featured in the film is Royal Scot Class No. 6115 Scots Guardsman.