HE is better known foul-mouthed spin doctor Malcolm Tucker, but Glasgow-born actor Peter Capaldi is swapping politics for intergalactic time travel as he takes over from Matt Smith to become the 12th Doctor Who.

Capaldi, 55, the first Oscar-winner to play the part, was revealed to audiences around the globe as the latest Time Lord in a BBC live special simultaneously broadcast from the US to Australia.

He will be the third Scot to play the role after Dunoon-born Sylvester McCoy, who played the seventh Doctor in the 1980s, and more recently Bathgate-born David Tennant.

Capaldi, a "lifelong Doctor Who fan" who wrote a letter to the Radio Times about the Daleks when he was a teenager, was the odd-on favourite for the part with bookies suspending bets on the Scot on Friday amid fevered speculation he would be the next occupant of the Tardis.

His appointment also comes despite rumours producers might break with tradition in the show's 50th anniversary next year and pick its first female Doctor.

The Thick Of It star said: "Being asked to play the Doctor is an amazing privilege.

"Like the Doctor himself, I find myself in a state of utter terror and delight.

"I can't wait to get started."

He added he was relieved the pressure of keeping the news secret was finally over.

"It's so wonderful not to have to keep this secret any more," he said as he appeared last night on the BBC show Doctor Who Live: The Next Doctor. "For a while I couldn't even tell my daughter who was looking it up on the internet, with people saying this person or that person should be Doctor Who and was rather upset they never mentioned me."

Capaldi has previously appeared in the series in 2008, playing marble merchant Caecilius in the Fires of Pompeii when Tennant was the Doctor. The show included an interview with current Doctor Matt Smith, who will leave at Christmas.

Smith said: "The casting of it made me really excited genuinely, and as a fan I think it's a really canny choice, so good luck mate, it's going to be a thrill. If I had to pick someone, I'd pick him, because I think he's great."

Steven Moffat, lead writer and executive producer of the programme, described it as an " incendiary combination". He said: "One of the most talented actors of his generation is about to play the best part on television."

The decision was also welcomed by Doctor Who companion Jenna Coleman, who said: "I'm so excited Peter Capaldi is the man taking on the challenge of becoming the Twelfth Doctor. I know we'll be making an amazing show with an incredible incarnation of No 12."

Capaldi will film his first scenes for Doctor Who this autumn, but will appear in forthcoming films The Fifth Estate and Disney's Maleficent. He is also filming a new BBC One drama series, The Musketeers, in which he plays Cardinal Richelieu.

He won an Academy Award in 1994 for the best short film, the comic Franz Kafka's It's A Wonderful Life, but really became a household name thanks to his performance as comedic anti-hero Tucker in the BBC satire of Westminster spin.

Writing on Twitter, fellow Glaswegian and Thick Of It creator Armando Ianucci said: "There can't be a funnier, wiser, more exciting Time Lord than Peter Capaldi.

The universe is in great hands."