Bang like a barn door in the wind. Get someone to cut those laces for you before you pop. He could feel himself reddening. “So what did you mean?” he asked, almost aggressively. “About them having an in with the Met?”

“Only that everyone says it round here,” Wildsmith said. “The word on the street, you know.”

“That King’s Cross nick is in the pay of Darby Sabini?”

“Well, that the police turn a blind eye. Warn them in advance of raids, don’t do much about complaints. My friend, the one I mentioned, was very irate on the subject the other day. He’s a pawnbroker. The Sabinis sent round some horrible thug demanding a weekly dole for ‘protection’, and threatened his wife pretty nastily when he told them to clear off. He ended up paying—as one would—and then went straight to the police.”

“And?”

“They just fobbed him off, he said. Haven’t done anything. His opinion is, and I quote, they’re all on the take, and the Met’s nothing but the biggest gang in London. He’s not very happy.”

“Dealing with protection rackets really isn’t as easy as it might seem, largely because the perpetrators tend to be good at intimidating witnesses,” Aaron said. “It takes a brave man to give evidence and stick to his story. As to bribery and corruption...” He paused, organising his thoughts, or perhaps his feelings. “It does happen. I don’t know of it happening in King’s Cross, or with the Sabini gang, but that doesn’t mean it isn’t. If the word on the street includes a name you can tell me—in strict confidence—I’ll act on it.”

“Really?” Wildsmith said, and then, “Yes. I dare say you would.”

“I—we—would have to. Policing is a contract. The public agrees to give people like me the power to ask impertinent questions, give orders, or even deprive people of their liberty, under a strict set of laws and circumstances and restrictions that govern our behaviour. If we don’t respect our part of the contract, the public can’t be expected to respect theirs. And if the public decides that the police don’t deserve to be obeyed, or that we don’t serve a useful purpose—well, you considerably outnumber us. Corrupt police officers don’t just harm individuals, they strike at the rule of law and the structure of society.”

Wildsmith was looking at him, eyes wide, lips slightly parted. Aaron felt suddenly self-conscious. “You don’t agree?”

“I agree entirely. I didn’t think that was the Met’s view. Don’t you get dismissed for calling attention to your colleagues’ wrongdoing?”