At the peak of the hill, Sherlock paused, looking ridiculously like a dramatic painting from years gone by. Tall and slender with his long coat flapping around him in the wind, framed from behind by the moonlight, and half in profile. But he spoiled that image by immediately dashing back over the hill to leave John behind, his much longer legs eating up the distance easily.

John would not have the chance to catch up before a car pulled up beside him, the motor purring smoothly and the tyres obviously having been refitted to deal with snow. A perfect marriage of luxury and need bundled into one car. The window wound down and a blast of hot air from the heating inside steamed out.

Anthea, Mycroft's assistant, glanced up from her phone as if she hadn't even realised he was there.

"Are you getting in then?"