‘Happy?’

‘The risk of infection is incredibly low, with the precautions we take.’

‘Low isn’t zero, is it? Nothing ever is, with our bodies. We’ll never be certain what caused my daughter’s tumour, and I won’t have her put at even more risk.’

Behind the anger, it’s obvious how scared she is, so instead of arguing with her, I’m backing away, towards the lifts.

‘Miss Parr? Angelica?’ Jed has stepped out of the classroom now. His stance is open, his tone soft. ‘I’m sure we can resolve this without raised voices. My students deserve a calm environment, and conflict isn’t helpful.’

Casey’s mum suddenly looks ashamed and I’m glad I kept my cool. ‘I’ll head off a bit early – it’s fine,’ I say.

Jed shakes his head. ‘No. That wouldn’t be fair to the children who are waiting for their turn with Bear.’

Casey emerges from the bathroom and smiles brightly. ‘Mum, why don’t we get a cappuccino downstairs? Is that OK, Mr Porter?’

Already she’s taking her mother’s hand and leading her away, going the long way round, so neither of them has to pass by me. She looks back only once and her face seems so sad, old before her time. Is her whole life like this – steering her mum around obstacles and avoiding fake danger?

As the other children gather around Bear again, I’m thinking about Casey. None of these kids have it easy, but it seems so wrong that she has to deal with so much on her own.

Bear’s jumpy after our session and being shouted at, so I let him sniff every plant and lamp post on the walk home. During his wild adolescent phase I got desperate enough to see a dog trainer, and she told me that sniffing is basically canine aromatherapy, helping to chill them out after stressful experiences.

As we potter along, I pass the entrance to the alleyway where I ran into the school group last week. And where I saw Casey’s dad, before I knew who he was.

A wave of heat passes through me. I try to distract myself by thinking about Angelica instead. They must have made a stunning couple. Even in the middle of her rage she was beautiful, with fair hair and the bone structure you see on supermodels.

He would never look twice at someone like me. On a scale of one to ten, I consider myself a seven and, though I thought Andrew was perfect, objectively he was a seven too. Relationships with a big difference seem high-risk to me.

How long did their relationship last? Fiery Angelica can’t be an easy person to be around. Dan might have tried to make it work before Casey came along. And he’s spending time with his daughter now, which most absent dads never do.

Why am I making excuses for him?

Bear cocks his leg for approximately the four hundredth time as we turn onto my road. Back in the flat, he goes straight to his bed and scratches wildly for a bit, before collapsing with a deep sigh.