Access was via the basement of an International Money Transfer shop on Dean Street. We didn’t wait and use a ram. Instead, Nightingale employed a nifty spell that caused all the hinges and attachment points on a reinforced fire door to simultaneous pop out of the frame so that the door itself toppled slowly backward into the corridor. He signalled me to wait before darting through – there was a long moment and then he told us to follow on.

It was a cylindrical shaft six metres across and twenty metres deep. The door gave in at the top, from where a modern metal staircase with sensible handrails spiralled around the circumference down to the base. It had been hiding in plain sight, marked on the construction blueprints as an emergency access shaft for the far end of the Crossrail passenger platforms. What it looked like to me was an inverted wizard’s tower, but I kept that to myself. There was an open-frame lift, like the ones used on building sites, that nobody wanted to be the first to use – just in case of booby traps.

The shaft was adjacent to the smaller shaft located at the end of Dean Street that Graham Beale’s brother had been found at the bottom of.

‘No floors,’ said Lesley.

‘They haven’t been installed yet,’ I said. ‘You can see the points where the load-bearing beams were going to slot in.’

‘What’s with him?’ asked Guleed.

‘He once arrested an architect,’ said Kumar.

At the bottom, placed in the exact centre of the bare cement floor. was a double-sized inflatable mattress of the type people take camping. It had been neatly made up with blue and white striped sheets and pillow cases, a duvet in a matching cover, clean, crisp – meticulously turned over. Next to it was parked an empty wheelchair and under the covers was Albert Woodville-Gentle, my personal number one suspect for the first Ethically Challenged Magician – the Faceless Man’s mentor. He was lying on his back, eyes closed, hands folded across his chest. Dead for about three days, Stephanopoulos reckoned – a timeline confirmed by Dr Walid, who rushed down from Oban the next day.

‘Natural causes,’ he reported after the tests came in. ‘Exacerbated by severe hyperthaumaturgical necrosis.’ Which was the next step up from hyperthaumaturgical degradation. So magic had put him in that wheelchair. He made a point of having Nightingale, Lesley and me in the lab when he did his brain transects – presumably as an awful warning. Nightingale said that Dr Walid always got excited when he had a new brain to play with.

But all that came days later. While we were still waiting for the forensics people Lesley asked the question that had been bugging me. ‘Why no demon traps? If it had been me, I’d have left a nasty surprise in hope of taking us all out.’