She hurried in the opposite direction until, out of breath, she reached Carshalton Ponds. The ponds lay under a leaden sky, two strange, shallow, purposeless, industrial-looking sheets of water separated from the road only by a railing, home to fractious ducks and gulls. Anna walked around them twice. I’m calming down now, she thought, surprised by her own resilience. He was only a boy. He was as guilty as me. To demonstrate calm to herself – to act it out – she bought a tuna wrap and an apple from the supermarket on the High Street. These she ate sitting on a bench by the water, while the young mothers more or less patiently urged their toddlers to and fro in front of her to feed the ducks. Sunshine came and went, but then it began to rain. To Anna, something smelled stale, perhaps the water itself, which had a light, cobwebby film, a skin of dust supported by surface tension; perhaps the birds pottering about in front of her. She hoped it wasn’t the children.

Carshalton is served by two stations; to reduce her chances of meeting the boy again, she decided against Carshalton Beeches and made her way up North Street to the other one. It was closer anyway.

Arriving home an hour or two later, she discovered Marnie in the garden, frowning puzzledly over the contents of the flower-border at the base of the summerhouse.

‘I don’t know where all these have come from. Did you plant them?’

Anna, who had anticipated having her house to herself and felt put out, first claimed to have no idea; then, feeling that she ought to show some kind of authority, though she hadn’t gardened for years, amended: ‘They’re exotics, darling. I think they’re doing rather well. Don’t you?’