Mark managed to find a good spot, in spite of how busy it was, on a sandy incline a little way back from the sea. He took a big blue-and-white striped beach towel out of his bag and unrolled it and sat down on it, and I took my own beach towel out of my basket and did the same.

We both looked at the sea. It was glittering invitingly in the sunlight, and was bright blue all the way to the horizon. Mark said, ‘I quite fancy a dip. How about you?’

‘Me? Oh, no, I don’t think so. I’ve never swum in the sea before. It might not be safe.’

‘But you can swim, can’t you? Jenny said you could both swim.’

‘Well, yes, we can. I can swim better than Ava, actually. I’ve got more badges than her, and I did lifesaving and she didn’t bother. But I’d still rather stay here.’

‘Fair enough. You’re on holiday, you should do what you want.’

‘Are you really just going to go off and leave me here?’

‘You’ll be all right, won’t you?’

‘Well, I expect so,’ I said with a shrug.

He looked at me through slightly narrowed eyes, as if having second thoughts, then suddenly got up and approached a woman who was sunbathing at a slight distance to us, reading in the shade of a parasol stuck in the sand as her child tottered round with a bucket and spade.

He said something I couldn’t quite make out – we’d done a little bit of French at school, days of the week and so on, but nothing that really equipped you for dealing with this kind of situation. Then he gestured towards me and I distinctly heard him say fille. That was girl, and it was also daughter. Had he told this lady I was his daughter?

The lady smiled and nodded and Mark came back and sat down again.

‘She said she’ll keep an eye on you,’ he explained.

‘What did you say to her about me, exactly?’

‘What do you mean?’

‘I heard you say fille. That means “daughter”, doesn’t it?’

I couldn’t decide whether I was angry or pleased about it. It was a bit of an insult to Dad, in a way. But I could see that it saved on explanations. And if Mark felt that way about us – if he was up for playing the part of being our dad – wasn’t that a good thing?

He narrowed his eyes again. I got the impression he was finding me hard-going, but trying not to show his exasperation. No wonder he wanted a swim.

‘I said belle-fille,’ he explained.

Beautiful girl? Why on earth would he describe me like that?

‘It means “step-daughter”,’ he went on. ‘I know it’s jumping the gun a bit. But you will be, one day. Anyway, I’m going to have a quick dip, if that’s all right. I won’t be long, and I’ll be able to see you from the sea.’