Ah, the big question ‘She . . . she’s somebody Daddy used to know,’ Frankie replied carefully, smoothing a hand over his springy wet curls, curls so similar to Julia’s it made her heart ache a little. Then she paused. Was it her place to say anything else here, or should she dodge the bullet and start discussing which bedtime story they would read tonight instead? ‘Um . . .’ she said, uncertainly. ‘So anyway . . .’

She had hesitated too long, though. ‘I don’t like that lady,’ Fergus pronounced, his face still in the bedcovers. ‘She said she was my mummy. But you are my mummy!’

Oh, help – here they were, right at the very nub of it, and she had no idea how to respond. Tell him the truth and break his world into a hundred confusing pieces? Or fob him off, leave the facts to be tackled another day? Frankie quailed at having been put in such an impossible position. But then again, hadn’t she put herself there, the very first time she let Fergus call her ‘Mumma’? She thought of Julia’s coolly enquiring eyebrow – He calls you that? – and took a deep breath.

‘Well, you are definitely my boy,’ she replied, heart thumping. Was this the right thing to say? Or was she making matters worse? ‘So I’m pretty sure that makes me your mummy. Hooray!’ she cheered, tickling his feet. ‘Because I really like being your mummy. ESPECIALLY . . .’ she added dramatically, ‘when you let me choose the bedtime story.’ She lay down next to him, so that her face was beside his, and put on a funny high-pitched voice. ‘Oh, please let me choose the story tonight. Please please please let me choose the story tonight!’

Fergus started to giggle, because this was one of their running jokes. ‘No, no, no,’ he replied bossily, squirming to get off the bed. ‘I am choosing the story. Because it is MY story,’ he said, scurrying over to the bookcase. ‘And I am choosing . . . THIS one!’

The dinosaur one again. Of course. ‘Excellent choice,’ Frankie said warmly, as he hopped back onto the bed and snuggled against her. She hugged him close and dropped a kiss on his head. ‘My goodness me, I am the luckiest mummy that ever, ever lived,’ she said, putting the book on her lap. ‘And do you know why?’

‘Why?’ he asked, sliding his thumb into his mouth.

‘Because you are the best boy that ever, ever lived. And actually . . .’ She walked her fingers down his plump little pyjamaed thigh, and he giggled again in anticipation. ‘You are also . . .’ Walk, walk, walk, went her fingers. ‘The. Most. Ticklish. Boy. Ever-ever-ever!’