‘Shit, that looks nasty.’ Callum caught hold of her wrists and held her two arms away from each other. ‘You mustn’t do that. You’ll hurt yourself.’

Leah’s chin dimpled with the effort of not crying. Her lips were dry from all the vomiting and the bottom one had cracked in two places. She could feel her blood pulsing tightly behind one of the splits.

A tear leaked out without her permission. She sniffed hard, but it was no good: it was merely an advance guard, not just for more tears but for words, more words than she’d said at once in days, maybe even weeks. The little bit at the centre of Leah that wasn’t drunk listened to the words with a detached horror. She could hear that they sounded slightly mad but she was too far away to do anything about it.

Callum fetched the box of tissues and did his best to make sense of what Leah was trying to tell him. As far as he could understand, the problem was something to do with control. Leah was out of control and the whole world was out of control and yet no one seemed to realise it.

‘Leah, is this something to do with you and Chris?’ He hoped it was; if Leah was heartbroken it would make this extraordinary outburst much less alarming.

‘Chris?’ Leah looked confused. ‘No, not about me an’ Chris. Iss about me, there’s something wrong with me.’

She was scratching again. Callum took hold of her wrists and held them firmly above her knees, trying to keep pace with this sudden change of direction.

‘What’s wrong with you? Leah? What is it?’

Leah shook her head.

‘Come on. You can tell me.’

‘Can’t.’

‘Yes you can. Come on. What sort of thing?’

There was a very long silence. Leah had her head twisted to the left and down so that there was no way Callum could meet her eye. Finally she said, in a voice so low he almost missed it, ‘It’s to do with sex.’

‘Okay,’ he said steadily, trying not to sound surprised. ‘What about sex?’

‘I don’ wan’ to say.’

‘Okay,’ he said again. ‘I understand.’

Leah just cried harder. Callum shuffled up closer and put his arm round her, pulling her head sideways onto his shoulder so that they couldn’t see each other’s faces any more.

‘Shall I tell you something?’ he murmured, as if talking to a small, frightened child. ‘There’s something wrong with me, too.’ He felt her shoulders tighten. ‘So how about we do a swap?’ Callum went on. ‘You tell me and I’ll tell you. Your thing can’t be worse than my thing.’

‘It is worse,’ whispered Leah.

‘How do you know that when you don’t even know what my thing is?’