Doctor Who star Peter Capaldi has claimed that the BBC is "not looking after" the hugely popular sci-fi show.

In recent years, Doctor Who has been shifted between autumn and spring schedules as well as alternating between split series. In 2016 it won't be on until its Christmas special.

The current Time Lord has noticed these dramatic shifts, believes it doesn't help the show, and now he's appealing to the BBC to take a more active role in order to secure Doctor Who's future.

"The BBC is an incredible organisation, but . . . sometimes people there think, 'That's looking after itself'. And it's not being looked after," Capaldi told Newsweek.

"I think maybe their eye was taken off the ball, or the show was seen as a thing they could just push around. It's not. It's a special thing."

The Scottish actor, a lifelong fan of Doctor Who, has been looking at the programme's fluctuating ratings in recent times, and he's not impressed.

And now he's insisting that the long-running show must remain "protected" by the BBC because it provides valuable family viewing.

"I have to pay attention to ratings - I'd rather not - but it's the way the business is," he said. "I think overnight ratings are a thing of the past.

"You can't really measure the success of the show by its overnight ratings, which is what the papers do. But there's still a place for families to sit down and watch the show - that's still a great, fun thing to do.

"That's what the show's success has been based on. That has to be protected."

Capaldi's criticism of the BBC comes days after he revealed that he's been invited to stay on as the Doctor once new showrunner Chris Chibnall takes over from Steven Moffat in 2018.

"To be perfectly honest, it's so far away in the future," he said. "You know, Doctor Who is a very difficult thing to say goodbye to - and I don't want to make that decision right now."