The Doctor travels time and space in a police box

They will be joined in their adventure by famous names including Stephen Fry, John Sessions and Jacqueline Pearce, who played Blake's 7 baddie Servalan.

Death Comes To Time will broadcast as six real audio files at the BBC's official Doctor Who website.

The files form a 30-minute audio play which sees the Doctor enlist the help of a mysterious Timelord (Stephen Fry) to battle an alien warlord (John Sessions) who is fighting for control of time itself.

Interactive

Listeners will also have the opportunity to review the drama and vote on whether they want the Timelord to return.

Richard Fell, Head of BBC Fictionlab, whose team produced the interactive event, said: "Since the programme first hit BBC screens on 23 November 1963 it has become an institution and we are sure that the Doctor's online regeneration will be warmly received by a legion of fans."

Sylvester McCoy picks up his seventh Doctor role

Doctor Who is the longest running science-fiction series in the world.

The Doctor's ability to regenerate himself has led to several actors playing the role over the decades, including William Hartnell, Patrick Troughton and Jon Pertwee.

Tom Baker was the longest-running Doctor, playing the part for eight years in the 1970s and early 80s.

In 1996 a US TV Movie starred Paul McGann in the title role. The Timelord's adventures have continued in books and on CD since the TV show was axed by the BBC in 1989.

The Doctor's best-remembered monsters include the Daleks and Cybermen.

Thousands of fans of the programme still attend Doctor Who conventions in both the UK and US to celebrate their hero.