Steven Moffat has revealed that the BBC are keen to commission a Doctor Who spin-off featuring Madame Vastra, Jenny and Strax, but he is reluctant for it to happen.

Speaking to Doctor Who Magazine in Issue 484 (out now), Moffat commented: “I’m always slightly worried that you can’t keep repeating the joke. And there’s always talk of the spin-off, and the Beeb would do it in a heartbeat… but… I dunno.”

He explained: “The moment you start relying on something, you should probably throw it away.”

The showrunner then hinted that it is unlikely River Song will be returning: “I always kind of feel that nothing should stay in the Doctor’s life. You can have River for a few years, but then River has to go.”

Moffat has also discussed why he’s chosen to increase the number of two-part stories in the new season of Doctor Who.

Season 9 began filming in Cardiff in January and will air on BBC One this autumn.

> Here’s everything we know about Season 9 so far.

Would you like to see a Paternoster Gang spin-off? Let us know below…