I hadn’t sensed anything from Lesley. Was it possible to mask a sequestration? Or, more likely, maybe I just wasn’t as sensitive as I thought I was. Nightingale was always telling me that learning to distinguishing vestigia from the vagaries of your own senses was a lifetime’s endeavour. I’d made an assumption about who was to be trusted – I wasn’t going to make the same mistake again.

After my shower I’d spent some time staring at my face in the mirror, working up the courage to open my mouth and look inside. In the end I closed my eyes and dug my fingers into my cheeks – I’ve never been so happy to fondle a bicuspid in my life. All that meant for certain is that Henry Pyke hadn’t stretched my face out yet.

I booted up HOLMES and typed in my access code and password. Technically both belonged to Inspector Nightingale and, technically, both should have been revoked as soon as he became inactive, but obviously nobody had got round to doing it yet – inertia being another key characteristic of civilisation and bureaucracy. I started at the beginning with the murder of William Skirmish, Covent Garden, 26 January.

I found what I was looking for three hours and two coffees later, when I was reviewing the Framline case. That attack had started with the cycle courier being knocked off his bike on the Strand and being taken to UCH for treatment, where he attacked Dr Framline. A uniformed PC had actually taken a statement from him at the scene of the accident while they were waiting for the ambulance to arrive. He’d claimed that a driver had overtaken him and deliberately forced him off the road. Lesley had told me that the accident had taken place in a rare CCTV blind spot on the Strand, but according to the initial report, the courier had been forced off the road outside Charing Cross Station. There hasn’t been a camera blind spot outside a London rail terminus since the IRA declared them legitimate targets in the 1990s. I went rummaging in the bowels of the HOLMES archive, where some demented soul on the Murder Team had uploaded the relevant footage from every single operable camera from Trafalgar Square to the Old Bailey. None of it was labelled properly, and it took me a good hour and a half to find the video I was looking for. The cycle courier hadn’t specified what make of car had crowded him, but there was no mistaking the battered Honda Accord that deliberately ran him off the road. The video resolution wasn’t good enough to show the driver or the licence plate, but even before I tracked its progress to the high-resolution traffic camera that guarded the lights at Trafalgar Square, I knew who it belonged to.