A sharp noise interrupts my thoughts. Joe is pressing the car horn again. I try to shake off the memory but, as I open the car door, the twisted feeling in my stomach, the one I always get when I think about Mark, remains.

‘Hello, beautiful boy,’ I say to Joe, who is resting his head on the steering wheel. ‘Shall we go inside and get a nice hot drink?’

He turns to look at me and his face darkens.

‘You go away,’ he yells, pressing his fist on the car horn.

‘Joe, stop being naughty,’ I say, leaning in to prise his fist from the horn. ‘That’s not a nice way to talk to Mummy.’

‘You’re not Mummy,’ he says, his face turning pink. ‘You’re bad person.’

At these words something inside me snaps. Almost four years’ worth of pain and sadness, anger and grief come spilling forth and I grab him by both arms and haul him out of the car. He screams and yells, kicking his legs into my stomach and headbutting my chest. It takes every bit of strength to keep him in my arms as I stagger towards the house.

‘Is everything all right? What’s happened?’

I look up and see Isobel coming out of the door, her face stricken.

‘Let go me … horble person,’ screams Joe.

He launches one mighty kick that catches me in the abdomen. I lose my grip on him and we both tumble to the ground.

‘My God,’ shrieks Isobel.

I’m completely winded and a sharp pain slices into my leg where I hit the tarmac. I stumble to my feet. Joe, apparently unscathed, has run to Isobel and is cuddling into her.

‘Are you all right, Lisa?’ she says. ‘That was a nasty fall.’

‘I’m fine,’ I say, brushing myself down.

Joe stares at me as I approach and as I look into his eyes I remember why I’d been so intent on getting to the pool that day. I imagine myself floating in deep water, all the pain in my body drifting away, and I know what I need to do.

‘Can I ask a favour?’ I say as Isobel stands looking at me, Joe’s hand in hers.

‘Of course,’ she says. ‘But I think you should come inside and clean up that knee. It’s likely grazed.’

‘It’s fine, honestly,’ I say, trying not to wince as the pain in my knee intensifies. ‘Listen, Isobel, would you mind looking after Joe for half an hour? I’ve got a bit of a headache and … a walk might clear it.’

‘Yes, of course,’ says Isobel, her eyes narrowing. ‘I’ve got some painkillers in my bag if you want some.’

‘No thanks,’ I say. ‘The fresh air should help.’

‘Are you sure?’

‘Yep,’ I say. ‘Absolutely.’

‘Okay,’ she says, looking at me warily. ‘Now, Joe. Shall we go and see if we can find some biscuits?’

Joe nods his head excitedly and I watch as they make their way back into the house, my shoulders lightening. Then I turn and start to walk.