The walk at the other end through the streets to my house was much quieter. The street lamps shone on parked cars and skips and front gardens. Once, on this route, I saw a dog fox at the end of a cul-de-sac. He stood silently with his noise pointed towards me and his ears delicately pricked. I was surprised by how big he was. After inspecting me he turned and vanished effortlessly into the darkness. Tonight, however, there were only cats and a couple of au pair girls hurrying back from an evening at the bar on the corner of the main road.

I was thinking about Mel as I walked, reviewing the little breach that I had caused and telling myself that it didn’t matter, it was nothing, our friendship was strong enough to weather it. If Mel had a fault it was her possessiveness, her need to feel that she was at the centre of her friends’ lives. Of course she would hate any suggestion that she was shut out.

The houses in my street had steps leading up to the front doors. As I walked under the clenched-fist branches of pollarded lime trees, I had glimpses of basement kitchens barred by area railings. I saw alcove bookshelves, the backs of computers and the occasional submarine blue glimmer of a television, but most of the downstairs windows were already dark. I reached my steps and walked up, my house keys in my hand. The lights in our house were all on. Lola must still be up.

I turned the Yale key and the door swung open. In front of me lay the familiar jumble of discarded trainers and shopping bags, and the council’s plastic boxes for recycling bottles and newspapers. Lola’s old bicycle was propped up against the wall even though she hardly used it nowadays, and one of the three bulbs in the overhead light fitting was still out. I had been meaning for days to bring up the stepladder from the basement and replace it.

Jack was sitting on the bottom stair. His face was a motionless white triangle under a stiff jut of hair. His arms were wrapped round his knees and his chin rested between them. His eyes fixed on mine.

‘Jack? What are you doing? Where’s Lola?’

My voice sounded sharp. The main feeling I had at the sight of him, out of bed at almost midnight, was irritation. He should be asleep. He should be recharging, ready for another school day. He should be many things that he was not.

‘Lola’s in her room.’

‘So should you be.’

I put down my bag and eased past the bicycle handlebars.

‘Why?’