‘Come on then,’ she said. ‘What do you want to say to me?’

I couldn’t tell her. I simply couldn’t get the words out. All I could say was, ‘I’m sorry.’

She sneered. ‘Sorry? Sorry? You think that means anything to me? Jesus Christ, last week you made me sign up to see a fucking therapist – who I didn’t go to see, by the way, so stick that in your pipe – because of my “issues”. But I was justified, wasn’t I?’ Her eyes blazed. ‘Everything . . . I was fucking justified.’

Quietly, I said, ‘Do you really think so?’

‘What?’

‘I know everything, Charlie. I know what you’ve done.’

She stared at me. ‘What I’ve done? What the hell are you talking about?’

‘Everything. Karen, for one. I’ve got evidence.’

She looked around, as if trying to see if anyone could overhear, but there was no one around, just a couple of thrushes pecking fruitlessly at the hard ground.

‘I have no idea what you’re going on about.’

A wave of nausea washed over me, almost dragging me under. I had the urge to put my head between my knees. An elderly man came into the park and walked past us. We watched him go.

‘Have you been fucking Sasha the whole time we’ve been together?’ Charlie asked. Her eyes had taken on a manic sheen. ‘How did you have the energy? The time?’

I shook my head. ‘You should have gone to see that therapist, Charlie. It might have helped your defence. Shown that you were trying to seek help for your problems.’

She gawped at me, her face full of shock and disgust.

‘I went to your flat,’ I said.

‘What?’

‘I met Fraser. He told me all about your relationship, about what you put him through. I guess that was the start of it. A kind of practice run. At least, with him, no one got hurt. No one died.’

‘I can’t believe you went to my flat.’ She pointed at me. ‘How dare you?’

‘I’ve been to Karen’s flat too, spoken to her neighbour. He saw you, can identify you.’

This was a lie, but I wanted her to believe she had no way to escape.

‘What the hell are you talking about?’ she said.

I stood up. ‘You should hand yourself in, Charlie. They’ll help you. You’ll get psychiatric care.’

But she wasn’t listening. She stared into the air beside my head, her mouth open, face flushed. Her eyes were darting about; I could feel waves of nervous energy coming off her.

‘Fraser is a lying shit,’ she said. She narrowed her eyes at me. ‘I love you, Andrew. You told me you loved me. You promised me.’

‘I do. I did.’