Sherlock showrunners Steven Moffat and Mark Gatiss share the thinking behind the Sherlock Christmas Special, The Abominable Bride…

Were doing it the other way around.

Steven Moffat:Sue was just giving us the options.

It was like, what would you do with the Special?

If there were three more coming later, could you do anything with a Special?

SM:We wouldnt be doing one like this unless it was a standalone Special.

You wouldnt take up a third of a series doing this.

[…] Then we thought, actually, lets not do that.

Lets just do it, lets do it for real!

Had they started out making a Victorian-eraSherlock,would this have been it?

MG:Yes, it would.

and there is a sort of perception of that.

Whereas, if you look at newsreel footage, London was busier than it is now.

The traffic is extraordinary.

It was completely choked.

It was a mad, bustling metropolis.

On whether there was ever any resistance to the idea of doing a Victorian episode?

SM:A little bit.

MG:We talked with the BBC, didnt we?

SM:And Sue [Vertue, producer].

Isnt it tremendously funny!

were not going to do that.

Were actually going to do areally goodVictorian one.

Its going to be really good.

Our objective was that ten, fifteen minutes in, youre going to forget that weve changed it.

Youre just going to be watching a really good Sherlock story.

MG:We thought, weve got room for a Special, with everyones timings.

We did talk about maybe doing three stories in one, and one of which would be period.

And then we just thought, what on earth are we talking about, this is a grand opportunity.

Was the plan to test out their existing show in a different environment?

Steven Moffat:Its more about having fun, to be absolutely honest.

Fun for us and fun for the audience.

MG:But we were very determined that its still our show.

Its essentiallySherlockas if wed always done it period, so it hasnt suddenly become very dusty and slow.

SM:Yes, its not a pastiche of other Victorian Sherlocks, its quite recognisably our version.

MG:We knew we didnt want to just do a sort of Comic Relief sketch.

It has the weight, it has the legs for it, and its a very good mystery.

Its a proper full-blooded Victorian Gothic.

On whether theyve been wanting to do a Victorian version for years:

MG:No, no.

That would imply that wed secretly been begrudgingly making it modern just so we could get to this.

Its just happened in this special way, that timing-wise for everybody its come off.

Could there be others or is this just a one-off?

[Laughter] With a speech from Churchill in it!

MG:And at the side it says Buy War Bonds In This Theatre!

Can Sherlock Holmes still be a scathing sociopath in a social climate as formal and polite as Victorian Britain?

SM:But thats what the original is like.

Thats exactly what he does.

Heshorrible.Especially in the earlier stories, he doesexactlywhat he does in the modern show in Victorian times.

And in the case of Sherlocks dialogue in particular, its not that different.

And my God, hes justmean.Hes just mean all the time to everybody.

Gradually, two things happen: you get used to as the stories go on.

MG:Its the same show.

Well be doing some visual pyrotechnics which are within the period.

SM:Certainly, its quite recognisably the same show.

It wont suddenly seem like a Basil Rathbone film or a Jeremy Brett episode.

SM:Better not get too excited!

And it works just as well in that context as it would in the modern one.

Its the same conversation.

A lot of it when you look at it, you think, it really is the same show.

Itreally isthe same, and yet every single detail youre looking at is different.

Even though weve changed everything, its still that.

Sherlock: The Abominable Bride airs on January the 1ston BBC One, time TBC.

The Abominable Bride round-table interviews withBenedict CumberbatchandMartin Freeman.