The British actor has announced he will no longer play the Timelord after he finishes filming four more special episodes to be screened in Britain next year and in early 2010.

Tennant, 37, is the 10th actor to play the role and has been hugely popular with fans of the long-running BBC sci-fi drama.

''When Doctor Who returns in 2010 it won't be with me,'' Tennant said in a video message to the crowd at the National TV Awards in London where he won the outstanding drama performance prize.

''The 2009 shows will be my last. I love this show and if I don't take a deep breath and make the decision to move on now, then I simply never will and you'll be wheeling me out of the Tardis in my bath chair.''

Bookmakers are already taking bets on who will replace Tennant as the Doctor in the fifth series scheduled for 2010, with Cold Feet star James Nesbitt, Life on Mars actor John Simm and fellow British actors Paterson Joseph and David Morrisey the favourites.

Tennant went on his first intergalactic adventure in the Tardis when he took over the role in 2005 from Christopher Eccleston, who starred as the Doctor when the BBC resurrected the show after a 16-year break.

Fans were left wondering in the last episode if Tennant would return in the role after the Doctor defeated his enemies the Daleks to save the universe and then began to regenerate but did not complete the process. Tennant will appear in a Christmas special, The Next Doctor, before filming his final four special episodes in January.

The show's long-time executive producer and writer, Russell T.Davies, said, ''I've been lucky and honoured to work with David over the past few years and it's not over yet, the 10th Doctor still has five spectacular hours left; after which, I might drop an anvil on his head. Or maybe a piano. A radioactive piano. But we're planning the most enormous and spectacular ending, so keep watching.'' AAP