He's probably cackling with glee about it at this very moment.
Though fans still don't have an air-date, the BBC Sherlock Christmas special is only a few months away. In an interview with Radio Times, he revealed a few details about the special that we didn't already have:
"Fans need not worry that the shift in setting will change the characters we know and love, adds Gatiss. "It's not suddenly going to be a different show. It’s essentially our Sherlock as if we’d always done it set in 1895. It has the same sensibility. The language is obviously slightly different but we wanted it to feel as funny and as vivid and as getable as our modern-day one. Otherwise it would be a sort of dusty period piece which is not what we are interested in. "The fall back in time wasn't something Gatiss and his co-creator Steven Moffat had always planned on doing (although it was a concept they'd toyed with "just for our own amusement.") It came about because of timing, and the rare availability of their now incredibly star-studded cast."
So, we know that they're deviating a little from their original plans for the show. But it also sounds like they never expected it to go this far at all. "The popularity of BBC1's reimagined Sherlock Holmes still comes as a shock to the drama's co-creator Mark Gatiss – "it's just astonishing... extraordinary."
Gatiss also discussed the difficulty of writing for a different time period.
The special – inspired by Rathbone and Bruce's Sherlock film series, which also moved between time periods –was "beautiful" but "oddly difficult" to put together, says Gatiss: "We’ve spent so long successfully modernising it. We had to sort of go back to basics."What we initially did was to come up with modern equivalents for all the Victorian things," Gatiss explained, "so in this we go back to the original. The texting is sending telegrams. We just reverse engineered it to how Conan Doyle did it." It sounds like a simple concept, but it seems it's already confused some of the show's followers: "The most incredible thing was when we did the press for it, three people said something along the lines of, ‘How can Sherlock Holmes possibly exist in a world without iPhones?’ I said, ‘Well, there is a slight precedent there!’
He's not mistaken there! The BBC series is actually a very close adaptation of the original stories. With the exception of the time period, many of the mysteries remain the same- in spirit if not literally.
"If we’ve successfully convinced the world that he’s a modern character then our work is done!"