Challice picked up a bit of battered onion and turned it in her fingers. “Would anyone listen to me? A detective constable, a woman, with a story like this? And...to be quite frank, bringing down a fellow officer is the kind of thing that ends careers, sooner or later. Everyone might agree he’s a bad apple, but nobody likes a nark.”

“That’s true,” Aaron said. “Not to mention, if you do it, I expect all women officers will be treated as potential snouts for a while. No. My career is over, whatever happens; I’ll do it, and take whatever shrapnel comes my way.”

“No,” Joel said. “That’s not fair.”

“It’s all right.” It wasn’t all right as such: it would be hellish and humiliating and he’d be all over the newspapers. But it had to be done, and Aaron felt a certain lightness at the decision, as though he’d let something slide off his shoulders. “I told you at the beginning of all this I’d do something about number seven, and I intend to. The question is how we make this work. Who I can go to who won’t be swayed by the Commissioner’s obduracy or Colthorne’s claims about me, and who’s prepared to face the trouble this will cause.”

“One of the Big Five?” Challice asked.

“The Detective Superintendents of the Met, based at Scotland Yard,” Aaron explained to Joel. “As far as I know they’re all decent men, but the DDI is on good terms with them. He’s been widely tipped to make a sixth. And any investigation would still have to be cleared by the Commissioner.”

Joel frowned. “Maybe if the information was already out there, it would be harder to brush it under the carpet?”

“Out where?”

“In the papers.”

“That’s a good idea,” Challice said, sitting up. “Do we know any journalists? What about those ones who called you Valentino, Mr. Fowler?”

“Oh, bugger journalists,” Joel said. “What about the editor of the Tribune?”

“You know him?”

“No, but I broke up his daughter’s engagement to an absolute arse a few weeks ago, so I’d say he owes me a hearing.”

“You mean Paul?” Aaron demanded.

“His fiancée was Barbara Wilson, daughter of Tony Wilson, who edits the Tribune. Did you not know that?”

“I try to avoid learning anything about Paul. Can you get me an introduction?”

Joel tapped his fingers on the table. “I could do that. But... All right, hear me out. Suppose I tell him I found the information myself?”

“You?”

“Let’s say Marks consulted me. Wanted to check if Colthorne’s handwriting on the IOU was real, something like that.”

“But he didn’t.”