Listen to RadioTimes.com's Doctor Who podcast: Spyfall – Episode One review

Click above for insight and analysis on the return of the Master (Sacha Dhawan) and his Tissue Compression Eliminator, the new-found 'confidence' of the Chris Chibnall era and the questions posed by the series opener – are we about the learn the true identity of the Timeless Child?

For more on Spyfall - Part One, be sure to read the nine burning questions we had after watching the episode. If you need a recap on the Master, you can read an abridged history of the villain here, and swot up on Sacha Dhawan - the latest actor to take on the part - with our profile here.

Doctor Who continues on BBC One on Sunday, with star Jodie Whittaker promising that "the questions will keep coming" as series 12 continues.

• Doctor Who hints at big new mystery – what is the Doctor’s lie?

After Spyfall - Part Two, the series continues with Orphan 55 by writer Ed Hime, who scripted 2018's It Takes You Away – and according to the cast and showrunner Chris Chibnall, it features a monster that ranks among the show's most frightening.

"Ed Hime has written episode three, which is called 'Orphan 55' and there are some monsters in that that are terrifying!" Chiball revealed. "They were there on-set, they're practical monsters."

"I was actually really scared when I saw one of them – I bricked it, I proper bricked it!" admitted Whittaker. :In rehearsal, he’s like six foot seven, in a suit and he’s running at you down a corridor and I was screaming."