Now Who will be the next Doctor?

David Tennant is to quit as Dr Who.

The actor who is currently making the third series of the programme, has told the BBC he will step aside halfway through filming of the fourth.

Tennant, 35, became the 10th Timelord when he took over from Christopher Eccleston last year.

He is said to be eager to take advantage of interest from Hollywood directors following his performance as Barty Crouch Junior in the third Harry Potter film.

BBC chiefs are keen on Robert Carlyle as a replacement Doctor, but are also said to be considering David Morrissey.

A BBC spokeswoman said it was too early to say who would star in a fourth series.