Life on Mars S02 E08 Episode 8

"Is he mad, in a coma… or has Detective Sam Tyler really travelled back in time?"

Sam learns that an operation is to be conducted upon him in 2006 to try and revive him from his coma. However, he believes that to return to the 21st century, he has to betray his colleagues in 1973 - but can he regard them as real or imaginary?