The thing about being a policeman is you get to cheat. You get to look things up on the PNC, things that even the richest and most influential person has to provide accurate information about—in this case, driving tests. Stephen George McAllister-Thames passed his in January, and the address of record was Chesterfield Hill, Mayfair.

It was the kind of perfect Regency terrace with a rusticated façade and decorative ironwork that causes grown estate agents to break down and weep with joy. It was located less than a third of a mile to the west of the Trocadero Centre, on streets that would have been much nicer if all the character hadn’t been stripped off them by decades of money.

The door was opened by a tall mixed-race young man whom I recognized off the picture on his driver’s license. He’d inherited an unfortunate pair of ears and what my mum would have described as “better” hair from his dad but he had his grandmother’s cat-shaped eyes—and that wasn’t all he’d inherited.

“Mum,” he called back into the depths of the house. “There’s a wizard here to see you.” And then, just in case I hadn’t realized he was a teenager, he slouched off back to whatever it was he was doing before I so rudely interrupted him. His mother passed him in the hallway and came and stood in the doorway with her arms crossed. She let me stew for a good ten seconds before asking what I wanted.

“I was wondering if you could help me with my inquiries,” I said.

She took me through into a kitchen furnished in French oak and cool green tile. She offered me tea, which just to be on the safe side I refused. She poured herself a white wine.

“What inquiries are these?” she asked.

I asked her to cast her mind back to her days as an undergraduate at Oxford University.

“Where I gained my double first,” she said. “Not that I think that was an achievement. Being less important than the mere act of being born within the sound of the Bow Bells.” She finished her glass and refilled.

“While you were at Oxford,” I said, “did you notice anyone practicing magic, perhaps clandestinely?”

“Does this have something to do with the altercation at the Trocadero Centre?” she asked.

“It’s related, yes,” I said. “And to the attack on Ash.”

“I’m curious,” she said. “What makes you think I should tell you?”

“So you were aware of magic being practiced,” I said.

“What makes you think that?”

“Because you think you have something to withhold,” I said.

“I’ll admit it’s a trifle irrational, but I still find myself minded to tell you to piss off,” she said. “Why should I help you?”

“If you tell me what you know I promise I’ll go away,” I said.

“Tempting,” she said.