‘I swear down, Mum.’ He stopped crying now; he was getting angry. ‘On my dad’s life. I swear I didn’t do anything wrong.’

‘OK. So.’ I looked back at the policewoman. ‘What happens now?’

‘It depends if Cecilia makes a complaint.’ She stood and tucked her pad away. ‘That will determine the next course of action, I’m sure you understand. We had to check out what the Jacksons had alleged happened last night.’

I saw her to the door.

‘And if Cecilia doesn’t complain?’ I murmured.

The woman, almost the same height as me, stood on my silly doormat that said Home Sweet Home and held my eye. ‘I do hope you won’t try to put pressure on her, Mrs March.’

‘Christ, of course not!’ I was beyond being offended though. I was just scared.

‘We’ll be in touch,’ PC Okoye said. ‘If there is a further allegation, then social services will also be involved. Let’s hope it doesn’t get to that. You’ll hear soon enough, I imagine.’

Utterly mute, I closed the door behind her carefully. Social services? My old colleagues?

From the living-room doorway, I looked at Zach, on the sofa, head in his hands, bare feet long and arched, resting on the floorboards Jonny had been so proud of when he’d polished them himself: that our downstairs neighbour had screeched about until we covered his handiwork with cheap rugs.

I looked at my distraught son, and I kept seeing his feet when he was a baby; tiny, soft feet, plump enough to eat. His delighted chortle when I pretended to.

Every instinct in my body screamed that Zach was telling the truth – and yet I knew that was the obvious reaction. The biased mother, unable to believe her child could ever do wrong: like Jan Vermaak. I couldn’t allow myself to fall into that trap. But oh, I felt cornered: the tiger, the bear, the wild cat pacing in the cage, unable to get out.

But I also knew Zach, I reminded myself. Honestly, I knew him inside and out; that’s what I believed, looking at him now. Everything I had done since he had been born, since Ali had been conceived by mistake, too early in my relationship with Jonny – only months in – everything was for them. Didn’t I know every cell of their body; the smell of their skin, their wide expectant eyes when they’d never seen any bad yet; milky breath at bedtime; snuffling in the night, like the baby hedgehogs in my grandma’s old garden in West Yorkshire.

We had been through so much together these past few years; how would it be possible for my son to be someone I didn’t understand at all? Someone whose behaviour I couldn’t predict or condone?

Whatever the truth, whatever had happened at the Jacksons’ house, I had to act to save him or it would be the end of everything as I had ever known it.

It would be the end of life itself, for both of us.