The CIA hadn’t given her the skills to spot a tail. She’d acquired those herself in the Garden City library, reading novels like The Thirty-Nine Steps and The Secret Agent over and over, soaking up everything they could teach her about spycraft. She’d put what she’d learned to use quickly, finally finding out where her brothers vanished to every day instead of working or looking after their mother. She’d followed them to a dried-up creek where they spent hours shooting at stunted bushes and sun-dazed lizards with an old revolver one of them had found somewhere. Then she’d made them teach her how to shoot it in exchange for keeping their secret.

The man made a good show of watching the world go by and listening to people talk about the end of civilisation and the healing power of Christ. But there was no escaping the fact that he and Bennett were the only people who had stayed on their benches and not moved on for several changes of speakers.

Knox was now late, but Bennett was less worried about that than she was about her tail following her to their backup meeting point in the Italian water gardens on the other side of the park. For all she knew, Knox was somewhere nearby, had also spotted the man shadowing her, and was purposefully keeping his distance.

She waited for the next natural shift in the crowd, chose her moment, and fell into step with a group of passing picnickers. Halfway down the eastern edge of the park she peeled off and crossed a wide, open section of ground. There were fewer people here, scattered and gingerly testing the grass to see if it had dried out from last night’s storm. She was exposed, but there was no other way to the Serpentine, the long lake that snaked across the park and led to the water gardens. She moved quickly, but not quickly enough—she hoped—to draw attention. It took her five minutes to reach a tree-lined section of path that gave her a little cover.

The Serpentine was choked with people. Families swarmed around deckchairs, couples promenaded along the lake edge, and groups of children chased swans. The surface of the lake was scattered with rowing boats.

Bennett crossed in front of a group of ladies pushing prams, all wearing dark dresses with starched collars. She glanced behind her and saw the man from Speakers’ Corner emerging from the path to the lake. She started to move faster, weaving between more groups of people. She followed the edge of the lake as it curved northwards towards the water gardens, stopping for a moment under the old stone bridge that cut the lake in two.