Hyde Park was close enough to Grosvenor Square for a lunchtime stroll whenever she needed to get her head above ground. And it was on one such walk halfway through a weekend shift in the archives that she encountered a line of people in the north-east corner of the park raised up on chairs, stepladders and, in a couple of cases, actual soapboxes, waxing lyrical to anyone who would listen. This was Speakers’ Corner, and it was a curious spectacle, both profoundly British and un-British at the same time. It worked as a kind of social pressure valve, letting the usually reserved people of London rant, vent, and rail about anything they wanted—within reason. The police monitored the speakers—particularly those who drew large crowds—but usually only intervened if their speeches crossed the line into profanity.

This Sunday a constant stream of orators offered benedictions, damnations, and prophecies to the passing crowds enjoying their afternoon in the park. Bennett had timed her arrival well. A couple of the speakers had just finished their speeches and their audiences were starting to move on. She had her pick of the benches and chose one that gave her clear lines of sight along the paths that converged on this part of the park.

A few moments later a man sat down on a bench two along from her. Like Bennett, he looked like someone who had been called into the office and was stealing a few hours of his Sunday back to enjoy the sun. He wore a light linen shirt and slacks, and carried a tightly stuffed document wallet. He was, Bennett had to admit, quite a good tail.

Bennett had realised she was half an hour early for her rendezvous with Knox as she’d raced out of the American embassy. So she’d taken her own meandering route to Hyde Park while she went over the implications of what she’d discovered about Finney and the sudden arrival in the city of a NASA scientist.

She’d first noticed the man following her when she’d paused in front of one of Selfridges’ windows, then again when she made a loop of Portman Square, just north of the department store. He blended well with the general street traffic, but not well enough for Bennett to miss him passing her in the Marble Arch underpass or appearing two benches down from her in Speakers’ Corner.