If some crazed scientist were to genetically engineer a drama to have an obsessive cult fanbase it would come out looking like Life on Mars. Combining the best elements of Doctor Who, Donnie Darko and The Sweeney with a teasing mystery at its heart, it practically demands you engage with it in a way you don't with other shows. Last night's breathless climax arguably proved less inventive than some of theories that have been circulating on Life on Mars online communities. Gene Hunt was driving the car that put Sam Tyler in his coma. Sam is his own father. Gene Hunt is the one in a coma and it's all in his head. Rarely has a TV programme been picked over in such forensic detail. Like Star Trek, Doctor Who and Buffy before it, it has a legion of fans who know the show better than its creators. With a possible feature film and an American re-imagining in the pipeline, not to mention Ashes to Ashes, an 80s spin-off for Gene Hunt, the show's DVD afterlife looks set to be a lengthy and intriguing one. For now, though, the fans must content themselves with their current favourite online sport - unearthing Life on Mars's anachronistic slips. Here, then, is small selection:

The Mancunian Way: When Sam wakes up in 1973 he is on the Mancunian Way building site. This road was completed in 1967.

The Ford Cortina: The dashboard from Gene Hunt's iconic Cortina is from a Mark 4 model, which only started production in 1976.

The CCTV camera: As episode eight of season one ends, a CCTV camera is clearly visible as the characters drive away.

The Three Degrees song: As the officers enter the casino in the series two opener, The Three Degrees' Year of Decision plays.

It was not released until 1974.

The WPC: Female police officers like Annie Cartwright were not referred to as WPCs until 1975. The correct 1973 term is PW (police woman).

The Watch: Sam's clunky Casio, a gold digital/analogue, did not make an appearance until the mid-80s.

The Dishes: Observant viewers have noticed some houses sporting satellite dishes.