Steven Moffat says Inside Man is "self-contained", won't rule out sequel

"The story will end in four episodes," Moffat said. "It's done by the end of that. As to whether or not you could ever spin off anything or do any kind of sequel? I don't know at this moment.

"It's not really up to me, and it's not up to the broadcasters – it's up the audience really, isn't it? And if anyone wanted it, you have to sit down and think, 'Is there anything to do?'

"Television is littered with shows that had one season and pretended they could carry on – I would never want to be one of those, where you're so excited to get a phone call about doing another run that you do it and then realise, actually, the story is finished."

Though the plight of troubled vicar Harry Watling (David Tennant) is likely to be resolved in the Inside Man finale, it's easy to imagine a spin-off exploring the further investigations of "death row detective" Jefferson Grieff (Stanley Tucci), who solves mysteries from behind bars.

It's possible, though, that Moffat might want to move on to a new original project – Inside Man is his first series not based on any source material since 2000's Coupling and the writer told RadioTimes.com that he had plenty of other ideas that were put to one side while he was serving as showrunner on Doctor Who and Sherlock from 2010 to 2017.

"There's a pile-up," he said. "I occasionally find them written on scraps and think, 'Oh, I should do that!' –it's one of the nice things about no longer doing Doctor Who and Sherlock all the time, which is what I did for seven to eight years.

"Every time I had an idea, I had to stand on it unless it fitted into one of those shows. I just quashed it and threw it away, so it's nice now, you can just think, 'Oh, that's an idea, I might go and do that, I might sell that.'"

Read more:

• David Tennant almost missed out on Inside Man role
• Steven Moffat reveals how his new TV detective is different to Sherlock
• Steven Moffat doubts Doctor Who return: "It's quite recent for me"
• Inside Man review: A dark, gripping thriller which earns its secrecy

Inside Man concludes tonight on BBC One and BBC iPlayer. Steven Moffat and Dolly Wells also feature in the new behind-the-scenes podcast Obsessed With... Inside Man, available on BBC Sounds.

Check out more of our Drama coverage or visit our TV Guide to see what's on tonight.

The latest issue of Radio Times magazine is on sale now – subscribe now and get the next 12 issues for only £1. For more from the biggest stars in TV, listen to the Radio Times podcast with Jane Garvey.