"I expected you to find out for yourself, boy." Then Angleton does something I absolutely never expected to see: he sighs unhappily.

"Boss?"

Angleton leans back in his chair. "Tell me about Chevaline," he asks.

"Chevaline?" I frown. "Wasn't that some sort of nuclear missile program from the sixties or seventies, something like that?"

"Chevaline." He pauses. "Back in the 1960s, when Harold Wilson cut a deal with Richard Nixon to buy Polaris missiles for the Royal Navy, the tacit assumption was that a British nuclear deterrent need merely be sufficient to pound on Moscow until the rubble bounced. During the 1970s, the Soviets began to construct an anti-ballistic-missile shield around Moscow. It was crude by modern standards: anti-missile rockets with nuclear warheads—but it would have rendered the British Polaris force obsolete. So during the 1970s, a succession of Conservative and Labour governments pushed through a warhead upgrade scheme that replaced the original MRV warheads with far more sophisticated MIRV buses, equipped with decoys and able to engage two targets rather than one. The project was called Chevaline; it cost a billion pounds back in the day—when a billion pounds was real money—and they didn't even tell the Cabinet."

"A billion pounds? With no oversight?" I blink rapidly. We're subject to spot audits on office stationery, all the way down to paper clips.

"Yes." Angleton smiles sepulchrally. "We helped ensure security, so that it was relatively easy for them to spend an extra two hundred million pounds in 1977 to keep the Concorde production lines at Filton and Bristol open for long enough to produce four extra airframes for the RAF," Angleton says blandly. "The Plumbers ensured that nobody remembered a thing afterwards."

"RAF 666 Squadron fly Concordes?"

"Flew them," Angleton corrects me. "The long-range occult reconnaissance model, not the nuclear-armed model the RAF originally asked for in 1968. You may not be aware of this, but Prototype 002 was built with attachment points for a bomb bay before the project was abandoned; Bomber Command wanted to replace V-force with a fleet of supersonic bombers that could carry Blue Steel nuclear stand-off bombs to Moscow, but the Navy won the toss. Instead, the RAF got the recon version, with supercargo space for the six demonologists and the optics bench to open the gate they needed to fly through."

My jaw is beginning to ache from all the speechless opening-and-closing cycles. "You're shitting me."