Pearl Mackie's Doctor Who codename revealed

That's why there's such a long history of codenames in Doctor Who. With clever use of anagrams and a healthy ability to lie through their teeth, Doctor Who stars and companions have (just about!) managed to keep their identities under wraps until the big reveal.

New Doctor Who companion Pearl Mackie was no different. Who casting director Andy Pryor, who has worked on the show since its revival in 2005, reveals that he, showrunner Steven Moffat and the team had a code word for talking about the new companion.

"Her codename was ‘Mean Town’," confirms Pryor. Hmm, wonder what the significance of that is? A reference to Ninth Doctor episode Boom Town? A little-known Prince track?

Not exactly.

"It's an anagram of Ten Woman," explains Pryor. "Series ten, and also the tenth companion of the modern series."

So there you have it, another piece of the Bill puzzle falls into place.

"These anagrams are becoming harder to think of but they’re always fun. It’s really so that nobody reads an email over someone’s shoulder and the name pings out at them," he adds.

"The fact is, if it’s a successful codename, nobody knows about it until afterwards," Pryor says. "It’s as much to amuse ourselves as anything else."

Come back to RadioTimes.com later for a full interview with Doctor Who casting director Andy Pryor, revealing why Pearl Mackie was picked to be the Doctor's new companion Bill.