Mark Gatiss and Steven Moffat spoke to the Cambridge Union on Friday, just days after the final show in the latest series had been airedQiuying Lai/The Cambridge Union Society

“Overnight ratings don’t mean anything anymore”, insists Steven Moffat. Neither he nor Mark Gatiss seem particularly fazed that the overnight ratings for the latest series of Sherlock were not great (the audience dropped from 11.3 million for the first episode, to only 6 million for the last).

But then, why would they be? Sherlock is, after all, a worldwide phenomenon, and one that Moffat and Gatiss are very much in control of. Certainly, the extent of this was made clear earlier this month when the Russian translation of the series’ last episode, “The Final Problem”, was leaked online. Fans were certain it was a hoax.

With an audience so accustomed to twists and turns that they were willing to believe that a fake episode of the show had been created, Moffat and Gatiss are under a lot of pressure to deliver. Still, Gatiss says, “we don’t think about it at all. We just try to make an entertaining program full of twists and turns”. And they are not particularly ingenious twists and turns, Moffat is keen to add: “Our big twist, which we got away with, was it wasn’t a brother, it was a sister. It’s not that clever.”

He continues: “I don’t think TV works or any sort of entertainment works if the audience actually feels outsmarted, that’s like you’re tricking them.” He explains the gratification the viewer must feel - to either be saying “oh, of course”, or “I got that”. But he notes that “it’s not that difficult in a TV program made over months to outsmart someone watching it for 90 minutes.

“Sometimes the very very best thing you do is a last minute improvisation”

Steven Moffat

Sherlock’s success is perhaps surprising giving the long gaps between series. Yet this has, if anything, only added to the appeal. “If you don’t give people what they want, they crave it more”, Gatiss explains, perhaps overlooking the fact that in reality, this factor to Sherlock’s success is a complete accident.

Indeed, the aim of leaving the audience wanting more seems to have been taken literally, but not purposefully. The sudden rise to fame of its stars, Benedict Cumberbatch and Martin Freeman, is largely to blame for the year gaps between series. Nonetheless, it is a ‘format’ that has “actually worked out quite well,” Gatiss jokes, turning to Oscar Wilde to explain the addictive nature of Sherlock: “The suspense is killing me, I hope it lasts.”

After the completion of the fourth series, with the possibility of a fifth series still in doubt, this could be the end of Sherlock. Have they always known this is where it would end? With a laugh, Gatiss responds in the affirmative, explaining that now the series has finished, “we can tell you that we’ve known [it would be] from the beginning.”

But Moffat is more serious: the plot of the fourth series has been known since the end of the third. While this happened to work out perfectly, not everything is immediately a perfect fit.

“Sometimes the very very best thing you do is a last minute improvisation,” Moffat continues, noting that his favourite scene in the series is one that was rewritten at the last minute. The original scene in “The Final Problem” revolving around Molly Hooper was hated by the rest of the crew, except for “me and Mark, who thought it was wonderful.” Moffat is glad they rewrote it, however. Not all of the best things are planned in advance.

“It seems to me strange to expect that Sherlock for some reason has to tick every single box”

Mark Gatiss

As is inevitable for a programme with such a global audience, Sherlock comes under a lot of scrutiny, and is often criticised for its lack of representation of women, LGBT+ characters and people of colour. But while Moffat and Gatiss are aware of this reaction and the calls from fans for the show to do more in this respect, Gatiss does not see why Sherlock must fulfil every criterion.

“The big thing to me is I don’t see why a program has to become a kind of grail for anyone’s expectations. It seems to me strange to expect that Sherlock for some reason has to tick every single box because I just don’t think that’s fair.”

Moffat, though, does add that he does think there is more space for this in TV in general. Switching briefly to discuss his other show, Doctor Who, he says it “can do more and should do more”. He is adamant that they are working hard to make it better.

But it is not about caving into activists or pressure groups - in his view, it is about “saying to children you are all welcome, and there are loads of people like you, and you belong out there in space, in the future. Not in the ticking boxes exercises. That’s not gonna work because it ends in what you call ‘tokenism’.”

He is quick to mention, however, that it is not the pressure groups that he is against. Indeed, he considers it important that they exist: “These things hugely matter. But because not everything the pressure group wants happens doesn’t mean people didn’t agree with them, it just means not everything is possible all the time.”

“But I think across the industry we are all trying to get better. It’s not always as easy as everybody assumes it is. But we are and we will and it will be better”