‘Did Dad tell you that?’ Tara almost laughed. ‘That is such a cliché. Women aren’t allowed to have a close friendship without men assuming they must be lesbians. Don’t be ridiculous. I would have noticed.’

‘It’s nothing to do with Dad.’ Toby was speaking slowly, as if she were particularly stupid. ‘The reason Dad left Mum was because she was found in a fairly undeniable situation with Diane.’

‘By who?’ This was surreal.

Toby was looking at her now with something bordering on pity. ‘By me.’

‘By … you?’

He nodded. The words hung in the air between them.

By Toby. Diane and Mum.

‘I was supposed to be staying over at Harry Jackson’s but his brother got food poisoning so they brought me home early,’ he said, in a matter-of-fact tone. ‘You were at a friend’s. Dad was away. I let myself in, heard something upstairs and …’ His voice trailed off and he shrugged.

Tara stared. She couldn’t picture it. Her brain refused.

‘It’s not the relationship,’ he went on calmly. ‘Who cares what people do, so long as no one gets hurt? It’s the hypocrisy. Mum always maintained what an unfaithful bastard Dad was, even after he’d left. As if she could rewrite history to make it his fault when she was just as bad! I couldn’t stand that, especially when you started to repeat things she’d said about Dad.’

‘Why didn’t you tell me?’

‘I tried.’ He lifted his hands. ‘I thought you had a right to know. Mum unsurprisingly didn’t. She basically told me that there were things about adult life I didn’t understand, that there was no point upsetting you even more and that if I did, it would be on me.’ He paused. ‘I was ten, Tara. And I hated it, by the way. I hated not being able to help you. I hated knowing something you didn’t. But I didn’t want to take away the comfort you obviously got from Mum so I said nothing. I thought it was the least bad thing to do.’

‘But Ashley …’

‘Ashley had nothing to do with Dad. She just drove him to the station. Although,’ he added, with an air of someone making a gesture of fairness, ‘it did turn out he’d had a thing with Ashley’s mum at one point. Like I say, neither of them were saints. And Dad was drinking, as we now know. So not making great judgement calls. I think one thing we can all agree on is that they were better off divorced. Better for them, anyway.’

Tara’s knees wobbled and she sank on to the kitchen sofa.

The world felt tilted. She’d always sensed there was more to her mother than she was able to reach, but this – this! – turned her into a complete stranger. It wasn’t who her mum had been.