Outgoing Doctor Who showrunner Steven Moffat has defended his decision to delay the introduction of a female lead by saying the show isn’t around to pander to “progressive liberals”.

This year's Christmas special will mark both his and actor Peter Capaldi's departure from the popular BBC sci-fi series, which he has worked on since 2009.

Viewers will instead be tuning in to get a glimpse of the first female Time Lord, played by Broadchurch star Jodie Whittaker, whose casting was first announced in the summer following calls to ditch the tradition of having a male Doctor.

Moffat, 56, who also worked on Sherlock, has now handed over the reigns to his successor, Chris Chibnall, and in an interview with the Radio Times he told how he toyed with the idea of casting a female Doctor himself.

The Scottish writer said he considered changing Matt Smith with a woman after believing that casting a woman after David Tennant’s spell may have been too early.

"We could have replaced Matt Smith with a woman, given that his Doctor was more sexless and less of a lad, but then I got obsessed with seeing Peter in the Tardis,” he said.