After breathing new life into one of television’s most loved brands, writer and executive producer Russell T Davies has announced he is to leave Doctor Who.

Staff writer Steven Moffat will replace him for the fifth series that will air in 2010 and Mr Davies will remain as executive producer for a series of special episodes.

BBC Fiction controller Jane Tranter said:

“As lead writer and executive producer, he has overseen the creative direction and detail of the 21st century relaunch of Doctor Who and we are delighted to have his continued presence on the specials over the next 18 months.”

The children’s science fiction series was on air from 1963 to 1989, with seven different incarnations of the Doctor, among them Jon Pertwee and Tom Baker.

Doctor Who was revived in 2005 with Christopher Eccleston as the eponymous time traveller. He was succeeded by David Tennant after one series.

Just last month Mr Davies was joking about the influence the revitalised show has had in Britain.

He dismissed the Independent on Sunday’s Pink List as “slightly demeaning” and laughed off their assertion that he is the most influential gay person in the UK.

The creator of iconic gay drama Queer as Folk, he is developing a new BBC drama series about forty-something gay men, it was confirmed last year.

Mr Davies is understood to be developing script ideas for the as yet unnamed series.

A BBC spokeswomen told MediaGuardian that it was “too early” to say which channel might the series would air on or whether it will be produced by an independent production company.

In an earlier interview with The Guardian Mr Davies said:

“It’s going to be about forty-something gay men and how jealous they are of gay teenagers. I’ve been longing to write something for adults.”

The Doctor Who writer and executive producer told the Guardian that the inspiration behind the new series is a friend, a former Mr Gay UK who split with his his boyfriend.

“He asked me: ‘Why are so many gay men so glad we split up?’ That remark’s stayed with me for six years. I think there’s a self-punishing streak in that gladness and I want to explore it.”

After this year’s Doctor Who, the next series will not air until 2010.