He opened it gently. ‘All these notes … I tried once, but I was no good. Think I just about made Grade 5.’ He shook his head in admiration. ‘I’d love to hear you play. Seriously, I think musicians must be the closest thing to angels.’

For a moment Tamsin thought it was a bad pick-up line; but one look at Chris’s face told her he was in earnest. She decided that she didn’t fancy him.

‘Are you going to be a professional?’

Tamsin nodded, then remembered to add a modest grimace. ‘If I make it. It’s pretty tough.’

Chris was impressed. ‘What about the rest of your family? Are they musical, too?’

‘My – yes, my mum’s a singer, actually. And my sister plays the oboe.’ Tamsin found herself reluctant to say who her father was.

Chris’s thoughts were rather more straightforward. He did fancy Tamsin, and he wanted to kiss her. She was tough and edgy and – a word that had powerful mystique for Chris – artistic. He was entranced. The more they talked, the more certain he felt that they had been brought together by fate and irresistible mutual attraction. Everything about the evening seemed tinged with inevitability.

They had had nothing to eat. By 9 p.m. when they stood up to leave, they were both fairly drunk. On the stairs, Chris dared a hand in the small of her back. Not wanting to embarrass him, Tamsin let it stay there; though she had a dim premonition that this would mean more serious embarrassment for both of them later.

But later never came. As soon as they reached ground level, Tamsin’s phone began to buzz.

‘Shit, loads of missed calls. Sorry—’

Tamsin wedged the phone between ear and hunched right shoulder, leaving her hands free to fumble with the zip on her parka. Chris could hear the low chirrup of the dial tone.

‘Mummy? Mummy, is that you?’

Her face went tight as she listened. ‘Okay. I’m coming home.’

Tamsin pocketed her phone and started on the zip for a second time. ‘I have to go.’ Her voice was hard and strangely adult, different from any other tone he’d heard her use that evening.

‘Is everything all right?’ Something warned him not to touch her again.

‘I can’t explain. Sorry. I have to go.’ It was a pedestrian-only road but she checked for cars out of habit, three quick pecks of the head. Chris called after her but she was already gone, over the street and into the bright tiled mouth of the tube station.

He didn’t have her phone number. He didn’t even know her surname.