When Tamsin was nineteen, her shoulders lost their angles; her arms and legs filled out; her nose and jaw took on a solidity that was unmistakably Bertrand’s. Her hair darkened to his exact shade of dirty gold, and even her newly swollen breasts appeared to belong more to her father’s side of the family than her mother’s.

Alarmed by the weight gain, Tamsin went to see her GP. She certainly wasn’t fat, but she was a lot bigger than she had been six months ago. Was it the Pill? Dr Lott didn’t think so. She scrolled briskly back up through her notes, rows of Listerine-green data on a convex black screen giving their laconic account of Tamsin’s life. Menstruation had started late, hadn’t it? This was probably just the tail-end of a mildly delayed puberty. ‘It happens sometimes. Nothing to be worried about. You’re a healthier weight for your height now, actually. It’s really not a problem.’

But it was. The mirror gave her back her father’s face, leonine, handsome, hated.

Four

The history teacher was called Callum Dempster. He and Tamsin met in the canteen of St Timothy’s, the East London comprehensive where Callum was deputy head of humanities. Newly graduated from the Royal College, Tamsin was playing keyboard in an Arts Council-funded workshop designed to introduce children from disadvantaged backgrounds to classical music. Callum was embarrassed that he’d never heard of her famous father; she was delighted.

After five years at Cambridge, one year in Berlin and nearly a decade in London, Callum’s Glaswegian accent was as strong as it had been when he left home. He hadn’t consciously held on to it, but he’d never tried to lose it, either: in his experience, it had always been a social advantage. At Cambridge, many of his privately educated peers felt reassured by his background. If someone like Callum could make it from a high rise on the banks of the Clyde to rooms in King’s, then the system wasn’t entirely unfair. He also added colour. Making assumptions based chiefly on Trainspotting, people would talk to him about drugs – only to learn that he didn’t even smoke. But a paracriminal prestige had clung to him anyway. Callum was tough, Callum was authentic, Callum was somehow more real than anyone who came from Wiltshire or Surrey or Hampstead.

Tamsin was a member of the Socialist Workers Party – something Callum teased her about so mercilessly that, six months into their relationship, she stopped going to the meetings. But she still read the email newsletters, and Callum still represented, for her, a vague yet unequivocally positive concept she called ‘the Real World’.

So she was disappointed when he landed his dream job: teaching Classics at a prep school near Chalfont St Peter, about an hour’s fast cycle ride outside London.