"To Be a Pilgrim"
From Tardis Wiki, the free Doctor Who reference
"To Be a Pilgrim" was an Earth hymn that the students of Coal Hill Secondary School sang in the morning assembly of Thursday 28 March 1963 to the "piano poundings" of music teacher Mrs Bellweather. Susan Foreman claimed the song had a special meaning to her. (PROSE: Time and Relative)
Behind the scenes
In the post-credits scenes of TV: Human Nature where John Smith entered Farringham School for Boys in 1913 and taught history, schoolchildren singing "To Be a Pilgrim" (backed by a church organ) was sung as incidental music.