While London Sleeps is a 1926 film about a police-dog, Rinty, who helps Scotland Yard

Scotland Yard

Scotland Yard is a metonym for the headquarters of the Metropolitan Police Service of London, UK. It derives from the location of the original Metropolitan Police headquarters at 4 Whitehall Place, which had a rear entrance on a street called Great Scotland Yard. The Scotland Yard entrance became...

 defeat a dangerous criminal organisation known as the Mediterranean Brotherhood that operates out of the Limehouse

Limehouse

Limehouse is a place in the London Borough of Tower Hamlets. It is on the northern bank of the River Thames opposite Rotherhithe and between Ratcliff to the west and Millwall to the east....

 district of London

London

London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

. Walter Morosco

Walter Morosco

Walter Morosco was an American film producer, writer, and director.Morosco was born in San Francisco, California, the son of theater impresario Oliver Morosco...

 wrote the screenplay

Screenplay

A screenplay or script is a written work that is made especially for a film or television program. Screenplays can be original works or adaptations from existing pieces of writing. In them, the movement, actions, expression, and dialogues of the characters are also narrated...

 and the film holds the distinction of being the first of many films directed by Howard Bretherton

Howard Bretherton

Howard Bretherton was an American film director, film editor, and the father of film editor David Bretherton. He began his career as a propman and then became a film editor during the early 1920s for MGM...

. The film was one of several created for Rin Tin Tin

Rin Tin Tin

Rin Tin Tin was the name given to a dog adopted from a WWI battlefield that went on to star in twenty-three Hollywood films. The name was subsequently given to several related German Shepherd dogs featured in fictional stories on film, radio and television.-Origins:The first of the line Rin Tin...

, a German Shepherd dog used in films during the 1920s and 1930s. Also starring are Helene Costello

Helene Costello

Helene Costello was an American motion picture actress, most notably of the silent film era.Lou Costello took his professional name from the actress.- Biography :...

 as Dale Burke, Walter Merrill as Thomas Hallard, John Patrick as Foster, Otto Matieson

Otto Matieson

Otto Matieson was a Danish actor of the silent era. He appeared in 45 films between 1920 and 1931.He was born in Copenhagen, Denmark and died in Safford, Arizona.-Selected filmography:...

 as London Letter, George Kotsonaros

George Kotsonaros

George Kotsonaros was a Greek-born film actor. He acted mostly in silent pictures....

 as The Monk, DeWitt Jennings

DeWitt Jennings

DeWitt Clarke Jennings was an American film actor. He appeared in 153 films between 1915 and 1937.-Biography:...

 as Inspector Burke, Carl Stockdale

Carl Stockdale

Carl Stockdale also known as Carlton Stockdale was one of the longest-working Hollywood veteran actors, with a career dating from the early 1910s. He also made the difficult transition from silent films, to talkies....

 as Stokes, and Les Bates as Long Tom.