‘Keep your voice down, you’re making a complete tit of yourself,’ Serena glared. ‘I knew you’d overreact when—’

She stopped herself but not soon enough. Tamsin had heard, and tipsy as she was, it didn’t take long for her to make the necessary mental leap. She leaned back against the banisters for support.

‘You knew. You knew,’ she said, her eyes widening. ‘That’s why you sounded so cool about it on the phone. I just got the biggest shock of my adult life and you don’t even break a sweat because you already knew.’ She was holding Serena by the shoulders now, just as she had done earlier to the boy at Denham Hall. This time, she actively wanted to inflict pain.

‘Tam, let go, you’re—’

‘I don’t give a shit if I’m hurting you. I can’t believe all three of you knew about this.’

‘We were going to – it’s just we knew how you’d—’

‘How long? Actually, no, don’t tell me,’ said Tamsin, abruptly loosening her grip on Serena. She held out her hand for her drink. ‘And don’t speak to me again this evening, please.’ She snatched the tankard roughly out of Serena’s grip and marched past her into the heart of the party.

For three hours, Tamsin successfully avoided both Serena and Will. She drank the punch, she talked for a long time to a boy who was very excited about some start-up selling a product he called ‘sausage jam’, she drank some more punch, she smoked a cigarette, she danced limply to the never-ending playlist of Swedish House Mafia.

She had just stepped out onto the crowded first-floor balcony to light her second cigarette of the evening when she heard Will’s voice loudly calling her name.

‘Tamsin Jarvis, I had no idea you were here!’

Tamsin whipped round to face him. ‘Vyoo fucked my lilsister?’

‘Is Callum about?’

‘Just answer me.’

‘Not that it’s any of your business, but no, I haven’t had that pleasure.’

‘You’re vile,’ said Tamsin, illustrating this remark by spitting a gob of tobacco-induced phlegm over the balcony.

Undeterred, Will squeezed in beside her, resting an elbow on the wrought-iron railing and placing his other hand on her waist. ‘Where’s Callum?’

‘Don’t know and don’t care.’ Tamsin tried for tough but she felt her mouth begin to quiver. She took a long pull on her cigarette to steady herself. ‘We’re over,’ she told Will, looking straight at him.

For a moment, she saw real concern in his face. But after second or two of calculation, recalibration, his features arranged themselves into a more conscious – and therefore less convincing – expression of sympathy.

‘Well, that’s dreadful news. I thought you’d go on for ever.’

‘So did I,’ said Tamsin. She began to cry.