I like a bit of drum and bass to dance to, but Various Artiz were notorious for cranking out one identikit track after another – they were as close to mainstream as you could get on the club circuit without turning up on a Radio Two playlist.

‘Don’t look at me,’ said Kumar to Reynolds. ‘It was all jungle when I was younger.’

‘It sounds like they’re speaking English,’ muttered Reynolds. ‘And yet—’

I knocked on the door and hurt my knuckles.

‘Well, that’ll work,’ said Reynolds. She was jiggling up and down to keep warm.

I took off my helmet and banged on the door with that.

‘We’re going to have to strip you off,’ said Kumar.

‘You’re kidding me,’ said Reynolds.

‘We need to at least wring out your clothes,’ said Kumar.

I banged a couple more times while Reynolds expressed her disquiet about disrobing in a public place. I can, when I have to, burn through something like a bike chain or a padlock. Nightingale, according to his war stories, can punch a hole in ten centimetres of hardened steel. But he hasn’t taught me how to do that yet. I examined the hinges on the door and wondered if they’d prove a suitable weak point.

I decided to do it quickly in the hope that Reynolds was too distracted to notice. I quickly ran through the formae a couple of times to line them up – lux aestus scindere. My mastery of aestus, which intensifies lux, was not brilliant but I really wanted out of the Underground.

‘Are you praying?’ asked Reynolds.

I realised I’d been muttering the formae under my breath, number six on Nightingale’s list of my bad habits.

‘I think he’s going to do a magic spell,’ said Kumar.

Making a note to have a word with Kumar later, I gritted my teeth as Agent Reynolds asked exactly what he meant by ‘magic spell’.

Oh well, it wasn’t like she wasn’t about to get a demonstration.

I took a breath and, silently, readied the formae.

Then the door opened and a white boy stuck his head out and asked if we were from Thames Water.

Thank god for that, I thought.

The instrument of the Lord was topless. A dayglo orange sweatshirt was wrapped around his waist, half covering baggy electric blue shorts, a whistle hung on a string around his neck and his sandy hair was slicked down to his forehead with sweat. Despite some muscle he still had his puppy fat and I figured he was in mid-teens. Automatically I checked out the bottle in his hand for alcohol but it was just water. A gust of warm damp air rolled out from behind him and with it the thumping back beat of Various Artiz seeking to prove that you really can dance until your brains dribble out your ears.