‘Sit still, darling, and hold on,’ Frankie said at once, slowing the swing before he tried to fling himself bodily from it. Fergus was very keen on the concept of presents. It had been his birthday in April and he still liked to talk about the occasion months later, often wanting to leaf through the cards again and examine photos of himself wearing a party hat, tucking into Frankie’s best effort at a Thomas the Tank Engine cake.

‘This is Julia,’ she added belatedly, in answer to his question. Oh God, she agonized as she lifted him down and the three of them moved a little way away, near the sandpit. Please let this be all right. Please don’t let Julia smash his world to bits with one ill-judged, impetuous remark. Please don’t let her try to snatch him away. She found herself glancing round to see if there were any mums she knew nearby, someone who could call the police for her, if Frankie had to give chase. If only Craig were here too, she despaired. At least they’d have safety in numbers then, a united show of defence!

‘Well, look at you,’ said Julia, crouching down and beaming at Fergus. She crooked a finger at him. ‘Do you want your present? Come and say hello to me.’

Fergus didn’t seem to like this idea, leaning against Frankie’s legs and sliding a thumb into his mouth. He stared at the floor and shook his head, no, and Frankie crouched down too, putting a protective arm around his small warm body. You can’t win him over that easily, love. ‘He can be a bit shy sometimes with people he doesn’t know,’ she said.

If Julia noticed the barb, she chose not to react, instead dipping a hand into a large canvas tote bag and drawing out a gift wrapped in shiny green paper. ‘Here you are,’ she said coaxingly, holding it out.

Still Fergus didn’t move. Frankie stroked his springy hair, finding herself checking out Julia’s shoes to gauge how fast the woman might be able to run, if she did make a grab for him. Gold high-heeled sandals with wispy, insubstantial-looking straps. Okay. They were probably safe. ‘Go on, darling, it’s all right,’ she told him. ‘It’s a present, for you!’ She dropped her voice to a pretend whisper. ‘And don’t forget to say . . .’

‘Fank you,’ he said obediently, stepping forward and taking the present. With a glance up at Frankie to check it was okay – yes, go on, you can open it – he tore apart the wrapping to reveal . . . ‘A bear,’ he said, with a noticeable lack of enthusiasm. Other children his age had bedrooms populated with whole jungles of cuddly toys, but Fergus had never been one for stuffed animals, preferring things with wheels that he could push around the floor, preferably crashing into one another.