In London, the weather had turned. Anna Waterman changed trains at Clapham Junction, and, taking the twelve-ten to Epsom, alighted at Carshalton Beeches. From there she walked east then south under a sky that looked like both sunshine and rain, through long suburban perspectives off which the dense ranks of detached and semi-detached suburban homes – each with its hundred-metre garden and mossy old wooden garage – stretched towards Banstead. Not far from HM Prison Downview she wandered into a street she thought she might remember, entering the garden of the first house she came to. It was three storeys, detached, with gable-front dormers, walls done out in whited pebbledash, and clean bay windows on the ground floor. Clean windows were a counter-indication: the house she was looking for, Anna felt certain, would have dirty, unused-looking windows, as if the person who lived there did not place a great premium on seeing out. It would be a house turned in on itself.

Neverthless she took the pocket drive from her bag just in case, and held it in one hand. If she was stopped, she planned to offer it as proof of her good intentions. She could say, ‘I came to return this,’ and it would be the truth. She was used to trespassing in people’s gardens by now. She had never been caught anyway.

A short, weedy drive gave on to the garage, and a front garden where ilex and old roses greened in a fitful light. Standing up at the bay window, squinting between her cupped hands to eliminate reflections, she found herself looking into a room full of partly-unpacked boxes and crusty dustcovers, as if someone had started to move in years ago and never finished. Items of furniture, including mismatched dining chairs and a hospital bed, were shoved up against the walls, off which hung narrow triangular strips of wallpaper stiff with old paint. Unplugged electrical leads curled and trailed about the floor. The upper surfaces of everything, from the treads of the stepladders to the shoulders of the unshaded light bulb hanging from the ceiling rose, were laminated with the gritty dust that collects in unused London houses, baking on year by year like a specialised industrial coating. The effect was of a room abandoned but not yet used. At the rear, a door lay open – wide enough to admit some light, not wide enough to see if a similar dereliction prevailed the other side of it.