Over the years, Sherlock has been drawn to a wide array of colours and tones. He finds deep neutral charcoal greys aesthetically pleasing. He often finds himself buying clothing in rich jewel tones - purple shirts, blue scarves.

For as long as he can remember, he's had a preference for deeper colours. They reminded him of a simpler, more straightforward time. The comforting dark red of Mummy's drawing room, the navy of Father's suits, before things got so strained.

There's an exception in the soft celadon shades of the wallpaper in his bedroom, which sometimes he suspects Mrs. Hudson hung in there because she knew he'd like it. If he were being honest, he'd admit that he's drawn to that range because it reminds Sherlock of his own eyes.

Some colours Sherlock finds fascinating are particularly morbid. Blood, the way the colour changes so drastically upon oxygenation. The grey-green of a bloated corpse, discovered too late to glean anything useful.

So Sherlock was quite surprised when on one quiet Saturday afternoon when John randomly asked him what his favourite colour was, he found his gaze lingering over John's warm, solid, reliable form in his favourite knit oatmeal jumper. Without thinking, without remembering all the colours that have previously impacted his life in one way or another, Sherlock simply blurted out "Beige."