There’s a strange atmosphere in the house in the days after Meddie’s accident: an unnatural stillness. I can’t shake the sensation that despite everything that’s happened already, we’re in the calm before the real storm.

I say as much to Tom as we’re getting ready for bed one evening a week or so later. The August night is sultry and humid, and the breeze from the open window too tepid to be refreshing.

‘You’re reading too much into what happened,’ he tells me. ‘How many times do we have to go over this? It’s summer, the kids are hot and bored, and I should never have left them to their own devices all afternoon.’ He strips off his T-shirt, and tosses it on the chair in the corner of our room. ‘Maybe Peter just got fed up being goaded by his sister, and gave her a shove to shut her up. You know what Meddie can be like when she presses his buttons.’

‘He could’ve killed her!’

‘He’s only ten, for God’s sake! He lost his temper. He didn’t mean to hurt her. Of course he shouldn’t have done it, but it doesn’t make him a bloody psycho.’

He knows that’s a loaded word for me, not just a turn of phrase.

Tom flips the covers back so far they fall off the end of the bed. The duvet is too warm for a night like tonight – I can’t wait for the Glass House and its air-conditioning – but the careless messiness of the gesture irritates me. I like getting into a properly made bed.

Tom wants to have his cake and eat it: he refuses to admit Meddie’s fall was anything but an accident, and yet he won’t let our son within ten feet of our daughter as she recuperates in her bedroom.

So it’s down to me. I’ve spoken to Peter, and made it very clear I’ll be watching him like a hawk from now on. I talked to him in the only language he understands: I will hurt you, I told him. If you ever do anything to harm your sister again, I will hurt you.

He believed me.

The problem is, I don’t believe it myself.

I’m a tigress when it comes to my children, just like any other mother: which of us wouldn’t do anything to protect our young? If someone threatens our child, we’ll crush their eyeballs with our thumbs and rip out their heart with our teeth if necessary.

But Peter is my child as much as Meddie. I could never hurt him, not even to save my daughter.