Peter Capaldi's Doctor Who is 'more like Sherlock', says writer Frank Cottrell-Boyce

Peter Capaldi is 'grumpier and a bit sharper' than Matt Smith's Time Lord

Peter Capaldi plays the Time Lord in the eighth series of Doctor Who (Getty Images)

Peter Capaldi's Doctor Who has become "more like Sherlock" according to episode writer Frank Cottrell-Boyce.

The British screenwriter, who wrote the 2012 Olympics opening ceremony, has spoken about the difficulties of penning a story for the sci-fi drama without having seen the new Time Lord.

Writers were told that Capaldi, who replaced Matt Smith in the role at Christmas, would be "older, a bit grumpier, a bit sharper", but otherwise all they had to go on was directions from showrunner Steven Moffat.

"The key note Steven gave was that whereas the other Doctors tell you what they're doing, he'll keep things to himself for a while," Cottrell-Boyce told RadioTimes.com. "Matt would tell you everything, but [Capaldi] keeps the process to himself until he acts on it."

With that in mind, Cottrell-Boyce imagined Capaldi's doctor as similar to Arthur Conan Doyle's super sleuth, who Moffat has also brought to life for the BBC with Benedict Cumberbatch in the lead.

"I guess he's more like Sherlock Holmes," he said. "The wheels are turning in his head but he’s not really letting you in on the process."

Benedict Cumberbatch stars as the lead in BBC drama Sherlock (Hartswood Films)

Having little else to go on, Cottrell-Boyce tried to keep Capaldi's voice in his head, but it was tricky.

"Obviously we wrote all of our scripts before we saw him," he said. "The minute [producers] had any footage of him they showed, but there’s an interplay between the writing and what he's trying to bring to it."

In an interview with The Independent earlier this year, Capaldi admitted that he was "constantly amazed" by his casting.

"I think, 'I'm Doctor Who, how did that happen?'" he said. "It's a huge privilege and hugely exciting. Every day is amazing."

But Jenna Louise Coleman, who stars alongside Capaldi as the Doctor's companion Clara, is rumoured to be leaving the show at Christmas.

The BBC has declined to comment on the speculation and Coleman is keeping storylines under wraps too.

"If you know I’m in the next series, or if you know I'm off, you'll know how the story ends," she said last month. "There's a big surprise coming. It's much better that nobody knows which way it's going to go, so that's where we're trying to keep it at the moment."

Cottrell-Boyce's episode of Doctor Who airs on Saturday 25 October at 8.20pm on BBC1