'It's going to be have to be a Doctor light episode. But so was Blink. Which some people seemed to like.' I'm paraphrasing from memory, but that was the gist of the direction from Steven. The implication being, this doesn't have to be a limitation. If you're smart, you could make it a strength.
I was two drafts into Flatline, which up until this point had been a conventional Doctor Who episode in many ways; the Doctor and Clara running around together and try to figure out exactly how to defeat the Boneless, the flat 'aliens of the week'. Only the version of the Doctor I'd been writing had been a generic vaguely Matt Smith version. Capaldi had only just been announced and this was supposed to be the meeting where I discovered Steven's vision for the new Doctor's character. And now this bombshell.
The Doctor needed to be in the same location for most of the episode. This would give Peter less shooting days and free up the schedule. Trapping him in the Tardis was the obvious choice. But how to make it seem a logical organic part of the story?
The five foot version of the Tardis was already in the script. 'Couldn't we just keep that process going? Shrink it right down, make the doors too small for him to get out?' There and then in the meeting I pitched the idea.
A tiny Tardis, but only on the outside. That could be kind of cool, couldn't it? We started riffing on the possibilities; the Doctor's arm reaching out, passing long things out like a Tommy Cooper gag, poking people in the eye. The mad thing was that no-one had done it before. In hindsight it seems obvious. The exterior has always been smaller on the outside. In this episode, we just keep going.
The next part of the puzzle came from Steven. I'm sure I would have figured it out given time, but he's just so damn quick. 'I'll go you one better.' he said. 'Clara carries the Tardis around in her bag for the whole episode.'
My smile froze. Of course she does Steven. And every time anyone compliments me on the idea I will have to hold my tongue and grind my teeth knowing you came up with the cherry on the cake. Damn your Bafta winning eyes.
Draft three was a lot of work. I had to completely rewrite the episode from scratch incorporating a whole new character for the Doctor based upon 12's new direction, figure out exactly how Clara would behave without him (Doctor Clara! Of course!) and make sure the logic of the tiny Tardis all held together.
A particular pain in the arse was the fact that anything the Doctor said to Clara couldn't be heard by other characters, which meant that repetition had to be guarded against. But on the plus side, he could insult with impunity. I think it was a three week rewrite, because we all knew it was a big one. I wrote every day until I got a headache. Which was most days.
An idea I came up with while writing was the Doctor dragging the Tardis along like the Addams Family Thing, which wasn't in any outlines or discussions and was a nice surprise for everyone when I handed in the script.
I think the rewrite was well received. A week or so after I handed it in I got a phone call: 'How would you like to write another one?' Is this a trick question? 'Steven's already got a title in mind. 'Mummy On The Orient Express.'...