While London Sleeps is a 1926 Warner Bros. film about a police-dog, Rinty, who helps Scotland Yard defeat a dangerous criminal organisation known as the Mediterranean Brotherhood that operates out of the Limehouse district of London. While the film has no audible dialog, it was released with a synchronized musical score with sound effects using the Vitaphone sound-on-disc process. Walter Morosco wrote the screenplay. It was the first of many films directed by Howard Bretherton, and one of several created for Rin Tin Tin, a German Shepherd dog used in films during the 1920s and 1930s. Only the sound discs to the film survive today with the visual film portions being lost. The British release prints censored the more horrific aspects of the film.

George Kotsonaros only appeared in two horror films, this one and The Wizard (1927), and he played a beast-man in both movies. He died in a car accident in Alabama in 1933.