This song was written by Nat Ayer with lyrics by Clifford Grey for a show,starring Violet Lorraine and George Robey, at the old Alhambra Theatre, which used to stand on the east side of Leicester Square. Great though the Odeon Leicester Square is, maybe it is a shame that the world could not have kept both of these buildings. As for the song: it was praised by Sir Edward Elgar, who called it a perfect melody and it has been recorded by many artists across the years and one of my favourite recordings is that made by Gertrude Lawrence and Noel Coward but I also enjoy the Stanley Holloway version and the recording by the rather forgotten Kathy Kirby. Besides those there is the piano roll recording by 1930s pianist Frank Milne. I have put links in the Youtube bar at the foot of this page but whether they work externally I cannot say. If they do not, it is easy enough to find them on Youtube.
The photograph is Stanley Holloway in a still from the great film The Titfield Thunderbolt.