He put his hand up. ‘What should someone do if they can’t walk away?’

‘Why wouldn’t you be able to walk away?’ said Jack.

Dave was silent. I was about to offer assistance when he said, ‘Maybe I’m minding the baby, and I have an anger attack. I can’t leave because I need to look after it.’

‘Dave, if you can walk away, walk away. Better to leave the baby for a while. But you need to calm down fast, that’s what I’m hearing. So, deep breathing, try to visualise a relaxing scene, talk to yourself, say a calming word or sentence over and over.’

Jack made us all choose a calming phrase, and practise saying it multiple times. Dave began saying calm, calm. It struck me that the word might have a paradoxical effect: it reminded me of someone trying to shut me down. The man on the other side of me began chanting in a language I could not identify, but one of the words triggered an association, due to its similarity to Ramanujan, the name of the eminent Indian mathematician. The Hardy–Ramanujan number is the lowest natural number that can be expressed as the sum of two cubes in two different ways. Mathematics. The unassailable world of rationality. As Jack passed, I was repeating the name of the number in the same tone as my chanting neighbour. The technique seemed to have the required effect; I felt distinctly relaxed. I mentally filed it for future use.

At the end of the class, Jack asked me to stay. ‘I want to know something. Could you have gotten out of that chokehold?’

‘Yes.’

‘Show me.’

He applied the chokehold and I demonstrated, without actual impact, three techniques for breaking it. I also showed him how to prevent it being applied, and a refinement which made it more secure.

‘Thanks. Good to know,’ he said. ‘I shouldn’t have done that, out there, you know. Bad example. Solving a problem with violence.’

‘What problem?’

‘Forget it. No problem. You ever hit a woman or a kid?’

‘No.’

‘I figured. You embarrassed a cop and they threw the book at you. Wasting my fucking time again. Ever thrown the first punch in a fight?’

‘Only in class. There have been three external confrontations, none of which required striking, excluding one with my father-in-law which took place in a gymnasium with appropriate equipment.’

‘Your father-in-law. Jesus. Who won?’

‘There was no judge or referee, but he suffered a broken nose.’

‘Look me in the eye and tell me you’re never going to hit a woman or kid. Ever.’

Dave had been listening. ‘Better he doesn’t look you in the eye.’

‘Go on,’ said Jack.

I looked directly into Jack’s eyes, while I repeated the promise.

‘Jesus,’ said Jack. ‘I see what you mean.’ But he was laughing. ‘I’m in deep shit if I give anyone an early pass out of this class and they reoffend, but I think I’m safe with you. Better for both of us.’

‘I don’t need to come back?’

‘You’re not allowed to come back. I’ll tell your social worker you’ve graduated.’

He turned to Dave. ‘I can’t make you come back, but you ought to think about it. You’re dealing with some dangerous thoughts.’

Dave and I detoured via a bar before going to our respective homes, as I would have aroused suspicion if I returned from a boys’ night out without smelling of alcohol. Dave had similarly not told Sonia about the Good Fathers Program.

‘There’s no reason not to tell Sonia,’ I said.

‘Best she doesn’t know. Men’s business.’

Sonia of course knew about the Good Fathers Program, but she couldn’t tell Dave without revealing the Rosie impersonation.

Rosie was in bed but not asleep when I arrived home. ‘How was your night?’ she asked.

I had solved one part of the problem arising from the Playground Incident and gained new knowledge. Dave had increased his self-confidence in dealing with conflict, although he had needed two burgers to recover from the trauma.

I wanted to tell Rosie all about it, but everything led back to the Playground Incident and Lydia. The potential of the revelation to cause stress had diminished, but I was now worried that a full explanation would reveal Lydia’s assessment of my competence in the father role, and increase Rosie’s own doubts.

‘Excellent,’ I said. ‘Nothing to report.’

‘Likewise,’ she said.

The martial-arts demonstration had reminded me of Carl and his attempts to surprise me with a punch. The routine had been mandatory on visits to Gene and Claudia’s, and inevitably ended with Carl immobilised and minor damage to decorative objects. Now, there was a risk that Carl’s punching ability would be applied to his father.

‘Have you spoken to Carl yet?’ I asked Gene the following evening.

Gene had purchased some port, which had three advantages over cocktail ingredients:

1. Existence. We had largely exhausted the supplies of anything alcoholic, except George’s beer.

2. Improved taste. Some cocktail ingredients are not palatable by themselves.

3. Lower alcohol than spirits. I had identified alcohol as the likely cause of recurrent morning headaches.

‘Carl won’t speak to me. Believe me, I’ve tried. There’s no way past the fact that I was unfaithful to Claudia.’

‘There’s always a way.’

‘Maybe with time. But it’s my problem, not yours.’