‘She was dreading it,’ said Calvin. ‘She thought it was the beginning of the end. No, the end of the end.’

‘I’m so sorry.’

He sat up and grabbed my hand. ‘Let’s get out of here.’

‘What?’

‘You eaten?’

‘No,’ I lied.

He drove me to a late-night place near Marble Arch, a Lebanese hangout where the proprietor hugged him like an old friend. I was to discover that this happened all over London.

It was midnight and the place still blazed with light. Shisha-smokers sat at pavement tables, zipped into flapping plastic rooms. I felt absurdly light-headed. I was young again, sticky from sex, eating baba ganoush with a man I hardly knew while law-abiding citizens were fast asleep.

Afterwards Calvin drove me through the deserted streets to the river and we stood on Waterloo Bridge. The clouds had cleared and a full moon hung in the sky. The city was ours, alone, as a distant church clock struck three.

Calvin was a man of impulse; I’d gathered that by now. As we leaned over the parapet, gazing into the water, he told me how, long ago, he’d met a woman in a bar. They’d struck up a conversation about Marilyn Monroe, and had a bet about whether she’d appeared in the movie All About Eve. He’d lost the bet and flown her to Le Touquet for lunch and a fleeting, afternoon fling, without ever learning her surname.

I was impressed. ‘You’re obviously not the sort of man who buys a copy of Which? before you invest in a tumble dryer.’

Calvin laughed. Of course I was jealous, but not stupid enough to let it show. Just for the moment he was mine. Besides, he’d said, ‘It’ll be better from now on,’ which promised more than a lunch in Le Touquet. We drove home, climbed into bed and slept until the afternoon.

And so began our lost weekend. Calvin didn’t go home that day, or the next. ‘Don’t you have any pets that need feeding?’ I asked, thinking of Evan and his charming, vet’s enquiry.

‘Only a feral cat.’ It was called Harrow, apparently, due to being found abandoned in a mailbag on the Harrow Road. ‘Angie had a soft spot for waifs and strays, bless her.’

Angie’s name had cropped up several times in our conversations but I couldn’t yet make sense of her. A party girl who jetted around the world on fashion shoots seemed impossible to connect with a doughty campaigner against climate change. Had she undergone a Damascene conversion one day whilst immersed in the hot tub?