It’s worth saying that there were a couple of things that influenced his creation. One (which works equally for Sherlock) is the story that Isaac Newton was so clever, so brimming with ideas that when he woke every morning he had to sit on the end of the bed with his head in his hands, just to let his mind ‘settle’. I think that’s just so thrilling as an idea and we wanted Moriarty to have something of that quality. Secondly, I remember when I was a child watching Peter Sellers being interviewed and he said something at once extraordinary and chilling. He was such a chameleon, such a repository for other characters and their quirks that he said to the interviewer “I THINK this is my voice’. Like a lost soul who no longer knows what he is. That sense of an empty human being with something dark and terrible inside him, Andrew can do like no one else.
—Mark Gatiss, co-creator of Sherlock on the show’s incarnation of Jim Moriarty.
