Doctor Who retirement seems to suit Steven Moffat. It’s been a while since we’ve seen him as relaxed as he is in this interview with the Doctor Who Fan Show, and with it comes the old wry Moffat wit – plus some amazing tidbits from his time in charge.

For instance, on the failed attempt to replace the ‘old’ copper coloured Daleks with larger multi-coloured models, he’s brutally honest about the failings.

“It was a salutary lesson,” he says. “The fault lies entirely with me, not the brilliant team who made the new Daleks. They were beautiful in many respects. But it was my mistake, and a completely unnecessary one… Now if you’ve seen those actual props, they’re gorgeous. If you see them on stage or in real life. Where they don’t look good is on television, the only place it matters that they look good!”

“It was a fascinating lesson I never forgot. We made the Daleks huge. Why? We make the Daleks huge and you just move the camera further away, and you make the Doctor smaller.”

He goes on to explain that the fault was in focussing on the wrong things in his first year as showrunner.

“We put so much thought and effort into our first block, episodes that I think stands up to this day – I took my eye off the ball of my block two episodes. I shouldn’t have been on that set, I shouldn’t have been giving endless notes on rushes that were unnecessary. I should have moved my attention to block two, taken a look at those Daleks’ camera tests. Most of the things I’m unsure about are in that block two, when most of my attention was on beginning. Beginning is easy, it’s keeping going that’s hard.”

Of course, that beginning might have been very different, if David Tennant had decided to stay on.

“David was going through the now-to-me very familiar angst about leaving, [but] it would definitely have been his last one.”

To that end, the plot would have been close to what turned into Matt Smith’s debut, with some significant differences.

“My version of that series would have been the David Tennant Doctor crashing into the back garden about to regenerate, and little Amelia would help him back to the Tardis and fly off.

“And then she’d meet him later, but he’d have no memory of that, because we’d come to realise that was the Doctor from the future and we’d make our way through the series to the point where the Doctor gets back to that.”

It’s an interesting ‘what-if’ for fans to ponder, and Moffat was keen to push back on the idea that every new showrunner must change everything just for the sake of it.

“Frankly if David and Catherine [Tate] had wanted to continue, I wouldn’t have [changed everything], it would have been the same design for the Tardis [etc]. Because there’s no way that version of the show was worn out.”

The rest of the interview, which covers everything from social media to the 50^thanniversary, is well worth a listen.