And then he was squealing and breathless, and throwing himself around on the duvet – and she was allowing him to get far too worked up, frankly, considering it was nearly his bedtime and she still had the dinosaur book to get through first. She’d pay for it ten minutes later, she knew, when she was trying to get Fergus to sleep and he was still hyper and silly, but right then, his face split open with rich chuckles and yelps, she wanted to live in the moment forever, and never, ever leave.

She and Craig discussed the situation in low voices after Fergus had eventually calmed down and fallen asleep. The whole incident in the playground was starting to feel like a bad dream now, but Frankie’s mind kept fixating on Julia’s wide, almost manic smile, the threats she’d issued in that friendly-sounding voice, and she felt distinctly uneasy. She wished Craig hadn’t been so impulsive about ringing Julia’s solicitor and telling her to shove her meeting. Frankie knew already that Julia was not going to be a pushover.

‘We’ve got to take her seriously,’ she warned Craig. ‘It’s not like she’ll fade away again into the background, just because we don’t want her around. And Fergus is asking me really hard questions – I don’t know how to answer him. Maybe . . .’ She swallowed, because she’d been dreading this moment. ‘Maybe he’s old enough to sort of understand that he has two different mummies,’ she said miserably. ‘Maybe we should just . . . have the talk. Then do our best to reassure him.’

Craig shook his head. ‘It’s too confusing,’ he said, drumming his fingers on the arm of his chair. He’d been in a grunge-band as a teenager and still played percussion on inanimate objects if he was thinking hard. ‘And as soon as we tell him about Julia, then we’ll have to let her into his life. Trust me, we don’t want that to happen.’

‘But . . .’ Frankie felt conflicted. Just because Craig hated his ex, was it right to keep her completely away from Fergus? Was he acting in good faith for his son, or out of revenge? He had once loved Julia after all. She couldn’t be that bad. Could she? ‘The thing is, I don’t think a court would actually refuse to let her see him, though,’ she ventured. ‘I mean . . . is that in his best interest?’

‘Yes!’ he cried. ‘Because she is a terrible mother. We have proof – solid proof – that she was crap. The fact that she bailed out on him so early, and has been entirely off his radar ever since. You can’t switch parenting on and off like that, out of some kind of whim.’

‘I know, but—’