‘I can still remember it,’ he tells her. ‘The Kellys’ annual Halloween party, we were all drunk on blood-red punch. I’d staggered out here in search of Charlotte. The bonfire was a smouldering heap at that stage, a few stragglers in fancy-dress weaving through the park. And there they were, Morticia Addams and Rob Roy, locked in a lusty embrace.’ He laughs, pleased with the image he’s summoned. ‘There was Ken wiping away her lipstick with the back of his hand, muttering: “Sorry, mate. I’m shit-faced.” But Charlotte just stood there staring at me, a prideful little smile on her face.’

He is warming to the topic now. In the cooling heat of the day, the park almost to themselves, breathing the free air, he lets his imagination roam. ‘It was one of the things I found so hard to take about Charlotte,’ he tells Leah. ‘The lengths she went to in order to rouse my temper.’

‘Is that how it happened?’ she asks him tentatively. ‘Did you come across her with someone? Did something just snap?’

Disappointment is instant. The positive mood that she always brings out in him instantly deflates.

She sees this, and adds, in a quietly defensive manner: ‘Even the most temperate man has a breaking point.’

He turns away from her and lets out a sigh. There’s a low wall by the tennis courts, and he goes to it now, drops his weight on to it. It’s so hard having constantly to fight this battle.

Wordlessly, she follows him, and he can tell that she is waiting for him to explain. He knows she wants to understand.

Tentatively, he begins to tell her about the day his world fell apart. He recounts it as best he can, willing his mind to travel back.

‘It was hot, and I was hung-over,’ he admits. ‘There had been a party the night before. I had drunk too much – we both had. Charlotte had been up to her usual tricks, drinking too much, flirting,’ he says, choosing the word carefully. ‘I tried to ignore it. I knew she was only doing it to get my attention – that was how she operated. But she wore me down. Eventually, there was a row between us and I left.’

He remembers Charlotte’s voice that night, shivering and vindictive as she made her accusations. Recalling it now, he feels a tightness in his chest, as if he cannot take a deep enough breath into his lungs. He would like them to resume their walk and to drop the subject entirely. But Leah’s expression is intent, and he knows he cannot lose her attention now. To pause would be fatal, if he is to convince her.