For a second, I consider telling her about it now. But then I hear a muffled voice behind her. ‘I’ll be right in,’ she calls to somebody. And then: ‘I’d better go, love. We’re about to do presents.’

I feel a spasm of panic rip through me. If I let her go now, I don’t know if I’ll ever get to speak to her again. But then what can I do? I can’t exactly spend the rest of this evening standing out here chatting to her.

I stare dumbly at the pavement, feeling my throat constrict so tightly that I can’t get any words through it. Luckily, Mum speaks for me. ‘It feels rather odd, not being with you today,’ she says. ‘Not having lunch together, not giving each other our presents in the morning.’

‘I know …’ I swallow the lump in my throat, and then remember the conversation I overheard through the kitchen door. ‘Hey, do you remember that Christmas when I was a kid, and I nicked your Sellotape and stapler and then gave them back to you as a present?’

The line is flooded with her laughter. ‘God, I’d forgotten all about that! What a little cheapskate.’ She breaks off and sniffs. I wonder if she might be crying, too. ‘You know,’ she says quietly, ‘that was actually one of my favourite gifts you’ve ever got me.’

‘I love you, Mum,’ is about all I can manage.

‘Love you too, darling,’ she says. ‘I’ll speak to you soon. Merry Christmas.’

‘Merry Christmas.’

I take a deep breath as I blink wetly into the night air. All I can think is: God, I hope I get to see her again. Just one more time.

My phone tells me it’s now 10.47 p.m. There’s just over an hour before all this ends and I find myself somewhere else completely.

Through the window of the bar, I can see Alice flagging our waiter down, signalling for the bill.

Once we’ve paid, we stumble back out, and Alice slips her arm through mine again as we wander tipsily through the near-deserted streets of the 14th arrondissement.

Occasionally we pass someone – usually another tipsy, looped-armed couple – and exchange a friendly Joyeux Noël.

We walk in silence for the most part. Alice is now seemingly all talked out, and I can’t conjure any words either. My brain is just white noise, like a scrambled TV. It feels like I’m on a conveyor belt; aware of where I’m heading, but not sure what will happen when I get there.

I glance down at my watch, its hands still stuck at 11.59. I’m about to check the real time on my phone when Alice stops outside a big blue doorway.

‘Here we are, then.’ She punches in the entrance code and looks me straight in the eye. ‘So … do you want to come up?’