In the final scene, the soundtrack that runs in the background is from Hindi film Rangeela (1995) scored by Oscar winner A.R. Rahman. The songs are 'Mangta Hai Kya' & 'Spirit of Rangeela'.
John Simm and Phil Glenister both appeared in Life In Mars and Mad Dogs. Marc Warren also starred in Mad Dogs as well as an episode of Life On Mars but doesn't do any scenes with the other two actors here.