On Monday morning I got up early and drove to Sarah’s house to put my letter to Harry through her door before she left for work.

She lived on a quiet street a couple of miles from my flat. As I approached her house I could see it was in darkness with the curtains drawn, and, like her neighbors, it seemed that she and her family were still sleeping. As quietly as I could I pushed the envelope through her letterbox and slid away in the early-morning mist back to my car.

I started to drive toward my flat, but when I turned on the radio and heard the six o’clock news bulletin, I thought of Harry and what he’d said to me one day.

“I wake every morning just before the alarm at six thirty,” he’d said. “Isn’t it odd how that happens? Every single day I wonder what’s woken me. And I lie there and my mind seems to scan through everything that might have happened. Was it my phone? Someone at the door? A car engine starting? And then, always, within a second or two, my alarm will go off. And that happens no matter what time it’s set for.”

“Is it an alarm clock?” I’d asked. “Does it make a slight sound, just before it rings?”

“No, it’s my phone. Hold on, though, let’s check.”

And he set his alarm for a minute’s time and we sat in silence, the two of us, leaning forward to listen, to check whether we could hear something, a sign that the alarm was going to go off. And then when it did, with a blast of “You Can’t Always Get What You Want,” I shrieked and jumped.

That evening I’d set my own alarm for the same time the next morning and I’d woken a few seconds beforehand, just as he did, and lay there in the soft darkness of my bed, with Tom lying beside me, still in a deep sleep. I thought of Harry in his own bed, lying next to Emma. I wondered whether they were lying close together, whether his arm had snaked around her waist in the night, or her legs were entangled with his. I turned to look at Tom, at his dark wavy hair, tousled on the pillow. He was lying as far from me as he could, and I’d been clinging to the edge of our bed in my sleep.