Within a month, it seemed, Robert had acquired the same jacket, the same shoes, and similar jeans to Paul’s. I didn’t tackle Kathryn about it, although I knew she must be supplying him with all these new items. Instead, I told her that I thought I could smell Paul in the house. A sharp, chemical smell. It reminded me of the smell in the turbine hall. She looked at me with a little smile. ‘That must be Robert you can smell, Howard,’ she said. ‘I bought him some shower gel. Aqua Fresh, or something.’

‘What’s wrong with soap?’ I asked.

‘Nothing,’ she shrugged. ‘He just asked me to buy him this instead.’

We’d promised him a trip to London for his twelfth birthday.

I’d been to London once, with Kathryn, before Robert was born. I’d wanted to take her somewhere glamorous, buy her something to wear, maybe take in a show. But I didn’t know where anything was. I only knew the words Carnaby Street.

I thought if we could just find Carnaby Street, we’d be bound to have a good time. We could do all the things I wanted to do there: the sun would be shining on the polished glass of the shop windows, and we’d stop somewhere for a coffee (which would be Italian, and would make a lot of noise as the waitress wrestled with the steaming machine). I didn’t like coffee much, but in London it would taste different. We’d sit in a café window and watch the other young couples glide by. Pop music – something by Dusty Springfield, or even a black singer like Sam Cooke – would be playing somewhere. And Kathryn would sip her coffee and look at me, and I’d squeeze her knee under the table.

But when we got there – after a three-hour bus journey – I couldn’t work out where we were. It was all so loud, so grey, and so wet. The traffic splashed mud up Kathryn’s new coat, and I felt every lump in the pavement through the thin soles of my best shoes.

In the end, we did find Carnaby Street. What I couldn’t believe was that it was so short. Just one little street with a few shops on. There was a coffee bar, but it was crowded; we had to stand up, and the sugar shaker was sticky from all the greasy fingers that had been there before mine. There was a lump of crusty sugar stuck inside the nozzle, so the crystals couldn’t shake out freely. I shook and shook, and all I got were a few yellow crumbs around my saucer.

Condensation ran down the windows, and everyone smoked. It wasn’t Dusty Springfield or Sam Cooke on the radio, but the Rolling Stones. I’ve never liked them.

But Kathryn drank a coffee, and as she sipped at her foam, she slipped a damp hand into my pocket, and we stood at the counter together, steaming.

So I thought I must plan this trip for Robert’s birthday with the greatest precision. I decided we’d splash out and catch the train. No three-hour coach journey via Sandhill, Wallingford and Henley-on-Thames for us – as diverting as those places may be. No stumbling off the coach feeling slightly sick, the streets swaying with the remembered rhythm of the coach. No. We’d sit back, Kathryn and Robert on one side, me on the other, and we’d relax as the countryside slid by; Sandhill, Wallingford and Henley-on-Thames would be nothing more than church spires in the distance.