IT’S SIX O’CLOCK, I’VE HAD A VERY LONG DAY ALREADY, AND I’M coming down in the world. That’s the only reason I can think of why I’m standing here, keeping my mouth shut, while a middle-aged shift boss bitches at me.

“I don’t believe this! I ask them for replacement cleaner who has corporate experience and they send me you! What are they thinking of in HR? You’re useless!” She’s pacing up and down in the breeze-block-walled janitorial room, pausing to periodically glare at me. “This is very exacting job! This customer is very critical! Why do they send me a man with no previous experience?”

We’ve got off to a great flying start, Eva and me.

“I can empty bins, vacuum, and dust,” I offer. “What more do you want?”

“You have no security pass!” Eva rounds on me. “Why have you not got a CRB check? You can’t clean bank offices without CRB! It say here you don’t have CRB!” She brandishes a dog-eared stack of forms at me.

“Oh, that.” Of course I haven’t been checked by the Criminal Records Bureau prior to employment by G4S Cleaning. I’m subject to Developed Vetting as a regular, recurring part of the security clearance for my job; as far as the CRB is concerned I don’t even exist. “Will this do?” I ask, hauling out my warrant card.

“What—” Eva stops in mid-flow.

“You will see that this warrant card identifies me as a plain-clothes detective inspector from the Metropolitan Police,” I tell her, extemporizing on the spot. “I am here as part of an official investigation by the Serious Fraud Office. You will not ask me any questions about why I am here or what I am doing. You will take me around the offices that Sara Siad cleaned on her last shift. If anybody asks about me, I am a new trainee and you are showing me the ropes. Do you understand?”

“But—but”—she runs down after a few seconds—“we don’t have trainees here!”