And I swear I could hear all of them breathing out suddenly, all the way from the monitoring room next door.

‘But from an art point of view it would have been better if it had smashed,’ said Ryan. ‘James looked at me then and it was in his eyes that “Oh well, bad luck you,” look. My failure made his success taste all the sweeter – it’s an American thing. I looked back at him and I think he must have seen it in my eyes, what was coming next, because he made his excuses and left.’ Ryan looked back down at his hands. ‘He ran, I chased, we got lost, I hit him with the plate, it broke, he tried to walk away – I stabbed him in the back. Is that what you wanted to hear?’

It was more than I wanted to hear, but police work is all about the details so I stayed another half an hour going over what he could remember of the chase and the exact sequence of events around the stabbing. None of it was admissible, but it could be used by the Murder Team to double-check the official statements.

After that, Nightingale sent me and Lesley back to the Folly for a sleep. By that time in the morning the slush-covered streets were empty and cold. As we turned into Charing Cross Road Lesley put her hand on my shoulder and said; ‘You did some proper policing there – Merry Christmas.’

Late Christmas morning one of Lesley’s sisters turned up to drive her out to Brightlingsea, where I was informed there would be the traditional turkey, crackers and family squabbles. Nightingale reported that Agent Reynolds had been invited home by an evangelical family at the embassy for much the same experience, only with more cranberries and hopefully fewer arguments. Kumar and Zach spent Christmas delivering Christmas presents to, and taking medical samples from, the Quiet People, and voilà another unwritten ad hoc arrangement was added to the metaphorical book in which we presumably keep them.

Nightingale presented me with a small package neatly wrapped in silver paper. He stood waiting with suspicious casualness but I wasn’t fooled. I was tempted to pretend I was going to open it later but you shouldn’t be that cruel on Christmas. Unwrapped, it turned out to be an original stainless steel Omega, antique, black and silver, automatic winding and therefore magic-proof and worth about seventy to eighty times what I’d bought him. Which was a slim-line Nokia, modified to have a battery interrupt and preprogramed with every relevant number I could think of including the Commissioner, the Mayor and his tailor, Dege & Skinner of Savile Row.