He gave a short laugh, and I joined in, feeling stupid. I then asked about the night I thought Clytemnestra had peeled herself out of the painting.

‘That was the first night,’ said Lloyd, ‘I didn’t see you after that. I can only apologise again. I work with the information I’m given.’

I looked out of the window at the weather, which was overcast but clear. I suddenly had a daring thought: I didn’t have to hang around to see Toccata at all. Technically I didn’t take orders from her – I was based out of Cardiff.

‘I think I’d better be leaving,’ I said. ‘Sno-Trac in the basement, you say?’

‘Indeed,’ he said, ‘I’ll take you.’

Lloyd took a long dog-catcher’s stick and a press photographer’s flashgun from under the desk, the kind that accepts flashbulbs the size of ping-pong balls. We crossed the lobby and passed through a small door, then took the stairwell into the bowels of the Dormitorium. It was noticeably warmer when we reached the second sub-basement as we were closer to the HotPot, and the copper heat-exchanger pipes made odd gurgling noises as valves automatically opened and closed. The iron stair rail, I noted, was warm to the touch.

‘Quite hot down here,’ I said.

‘Cold snap on its way,’ explained Lloyd, ‘the rods are out in anticipation.’

‘Expecting trouble?’ I asked, indicating the flashgun and dog-catcher’s pole he was carrying.

‘The Sarah Siddons is only at sixty per cent occupancy,’ he confessed, ‘so I take on “basement lodgers” for a fee.’

‘Basement lodgers?’

‘Nightwalkers from the Dormitoria this end of town. Other Porters find them and park them with me until HiberTech or the Consuls get involved. I’ve got six, all told. Unusually high, I know. Morphenox isn’t totally without faults, is it?’

He was making comment on the fact that only those on the drug ever walked. For every three thousand or so who felt the Spring sunshine on their faces, one would be a nightwalker, and no one considered those odds anything less than acceptable.

‘I’ve been feeding them a turnip and three Weetabix a day, so – fingers crossed – they haven’t yet resorted to eating one another.’

I hadn’t thought for one moment I was going to have to run the gauntlet of potentially cannibalistic nightwalkers, and told him so.

‘Don’t worry,’ he said, ‘even a child could outrun them. Just make sure you’ve no chocolate or Oxo cubes in your pockets. They can smell them a mile off; drives them nuts.’

We arrived at a steel door which had six names chalked upon it, along with the dates they were locked in. Lloyd dug a flashbulb from his jacket pocket and pushed it into the reflector bowl.

‘I trigger it manually,’ he explained. ‘The bright light scrambles the remnants of their brain long enough to get away if needed.’