I plotted it, the whole thing.

Steve[n Moffat] agreed, and it crunched down.

What I did do was an early draft where it was basically just the Doctor and Clara.

It was a bit likeThe Ark In Space.

It was just them exploring this empty space station, because you have time to do it.

Whereas traditionally you have to wrap up.

It needed a kind of immediacy really.

Its an interesting thing.

The shows been back on for ten years now, and weve become much more used to that.

It was initially quite hard to unpick that mindset.

But I think in the end it really benefits the episode.

As I said, found footage is familiar in films now, but its never done in TV.

Its great that it can still do that.

And it really suits it.

That would normally be a series of things, but you could just cut in.

I found that really exciting.

In some way, particularly withCold War, that is absolutely a haiku version of an old episode one.

You actually have to be prescriptive.

We want to keep reminding people its not like an ordinary episode.

I didGhost Storiesa couple of years ago, and Id love to do some more.

But to be honest, it was quite enough to do this episode.

And I suppose its an appealing idea, but its pretty terrifying.

Id call my episode Dont Fuck It Up [laughs].

But I think Justins done a brilliant job.

Im really pleased with it, I think its come out really well.

Then I really didnt.

Im thrilled with how scary it is.

Theres a section in there, where they hide in the cold store in the kitchens.

Ive been trying to do that for years.

I had the idea years ago what a great place to have a set piece scary thing.

Because all you see is the breath, and its logistically not impossible.

And we finally did it.

They were very cold!

But as I say I think its come out really well.

And I love the monsters!

On whatSleep No Moreis about:

Its a satire on our working lives.

In the future, well have no time at all.

Well have to work all the time.

Really what humanity is doing is bartering away the most blessed thing there is: sleeping.

Shakespeare and all the poets were right.

Theres more to it than we know.

I went to see him, and he said Mark, where did you get your shoe.

Just the one?, I said.

He said I have one of those.

And then he said: Well, they dont think the other leg will last to the summer!

He never lets you down!

Where are you in terms of futureDoctor Whostories?

Ill see if I can do that.

Its always the same way, really.

You have a store of ideas that are nuggets, or others that might be slightly more thought out.

And then its what might fit the season.

Ive actually talked about [Sleep No More] for quite a long time.

Ive got a few ideas!

Id love to do a story about fracking.

When I first heard about it I thought ofInferno.

To me that sounds a veryDoctor Who-y idea, that.

Its obviously a bad idea.

To me its got that wholeJawsscenario, of lots of people saying its going to be fine.

But as well as shale gas, maybe theres something else lurking down there.

Its called Frack Off And Die [Laughs]

Thats all it is.

Thats an idea, its not fully fledged.

Do you think youll do a sequel toSleep No More?

Theres a bit of a history of groupings.

Theres two Mara stories in Peter Davisons time.

It would be nice to.

I think the idea is good and the monsters are great so it would be quite nice.

I suppose youd have to do aWeb Of Fear-punch in thing where you ask where else could they go?

But the Doctor loses in this episode.

And thats an unusual place to be.

And so it also needs some closure.

Mark Gatiss, thank you very much…