I crawled into every corner of my imagination to find out what made [Holmes]. I have this whole history of him as a child which I used to fill this chasm—to find out what he’s made of. He’s very private. To help to discover what he’s like inside I had this whole story of his life. He was tied very tight as a child in the cot as they used to do in those days to keep them quiet. Children were seen but not heard—especially in the Holmes household which I’ve always placed in my mind in Cornwall … very remote. A bleak house. Never knew his father at all until he was 21. Saw him but never spoke to him. He had an elder brother who was fat and a little bit far ahead of him. They didn’t have much in common either. They were kissed by their mother on her way down to dinner, but that’s all. Typical Victorian upbringing. I think that he had more in common with his mother—she was the brains—but, of course, women were not allowed to say much in those days and this reserve rubbed off on Sherlock. His father was a fat, ex-army toad, I think.

Anyway, he escaped to Eton— or one of the major public schools. He was a spidery person, with no colour in his face, no friends—scared of friendship—but brilliant at certain subjects. Brilliant at fencing and boxing, but always the person who walked away from personal encounters. He was devastatingly unattractive: white as a sheet, spotty probably, with all the complications of puberty and no one there to guide him through it. Probably loved singing and joined the choir.

University. I would plump for Oxford. Oxford id darker. Cambridge is too full of light. Then brilliance—growing—mind developing—debating societies. Probably saw a girl—a woman, whom he fancied, but she didn’t see him. That one rejection did it. The one time he placed himself in a vulnerable situation and to see her turn away and choose someone else snapped the door shut like a steel trap, never to be opened again. What should he do now? Return home to his family and take up some dreary duties associated with the estate. He wanted to escape that, Mycroft, ahead of him, had escaped: he’d waddled out of university to get a junior post in the current government. Mycroft also joined a club only a Holmes would join—one in which no one spoke. Sherlock, isolated as he was now, forced himself to find his own way—his own job—and therefore become himself.

As Watson bellows Holmes’s name repeatedly over the falls, we see Holmes clinging to the hillside some distance away, watching his friend. At one moment it almost seems as though he is about to respond with a cry of ‘Watson’, but then he stops himself. Brett explained:

‘That was deliberate. It wasn’t in the script but I just wanted to show that Holmes had affections for Watson and for a fleeting second they almost get the better of his practical mind. But they don’t. [Large Brett grin.] It is a moment.’