Steven Moffat has revealed he has always wanted there to be an episode of 'Doctor Who' based solely on the TARDIS ever since he was left "disappointed" during his younger years when classic adventure 'The Invasion of Time' failed to live up to his hopes.

Steven Moffat always wanted to set an episode of 'Doctor Who' solely in the TARDIS.

The showrunner commissioned 'Journey to the Centre of the Tardis' by writer Stephen Thompson after he was left "disappointed" during his younger years when classic adventure 'The Invasion of Time' promised to reveal the "many rooms" of the time-travelling craft, but set design issue meant many of the scenes were underwhelming as they were filmed in an old hospital.

He said: "I remember years ago ... in the Radio Times there was a little article saying, 'In this week's episode the Doctor dodges the Sontarans through the many rooms of the TARDIS.' I could not wait for Saturday.

"But there was a problem with the scenery or something and they shot it all in a disused hospital. And it was so disappointing. And I thought that day, 'Some day! Somehow, I will do what I can to get into television and do that properly!' And that worked out. So Michael Pickwoad [Production Designer] goes mad and gives us the TARDIS and gives us all manner of things."

Steven says 'Doctor Who' fans will see the titular Time Lord's time-travelling machine "more properly" than they ever have before in the forthcoming episode.

Speaking at a Q&A held to launch the new series of 'Doctor Who' in London, he added: "You will go to the heart of the TARDIS. You will see more of the TARDIS more properly than you've ever seen it before. It's all that stuff. The moment I got that title and gave it to Stephen Thompson, who wrote it, it was just the title alone gets you."