I take a deep breath. Even though I know that Sheena Dawson suffered from depression well before Alice died, her younger daughter’s tragic death must have catapulted her into the darkest place for the longest of times and I can’t help feeling guilty about that. Because I could never give her what she needed. I could never tell her what happened.

“They must be very proud of you, being a nurse.”

She nods. “They are.”

“You used to work as a secretary, didn’t you? What made you go into nursing?” I keep my voice as casual as I can, aware that my heart is beating faster. Surely she must realize that it’s the last career I would ever have imagined her pursuing.

She sighs. “I suppose it was because of Mum. Her depression forced me to take responsibility for things from a very young age. I had to help Dad look after her. And when Alice came along, I looked after her, too. Dad worked long hours at the shop and Mum wasn’t up to much at all after the birth.”

A crow swoops across the sky and lands on one of the chimney pots of Charlton House. A few seconds later, it’s joined by two more. The three of them screech at one another and Catherine and I both look up at the same time.

I steal a glance at her from the corner of my eye. It wasn’t exactly the happiest household even before Alice died. If Sheena Dawson wasn’t lying in her bed in a welter of depression for weeks on end, she was distant and uptight, more concerned with cleaning the house from top to bottom and despairing over the state of their garden than with the emotional well-being of her two daughters.

“It must be nice to have a vocation,” I say, trying to steer the conversation back onto safer ground. “I’ve never really worked out what it is I want to do with my life.”

“Why do you think that is?” she says.

“I’ve no idea. Perhaps I’ve let my seizures hold me back. Or rather, the fear of them.”

Catherine doesn’t respond. It was the wrong thing to say. The only seizure I can think of right now is the one I had at the railway crossing. She must be thinking the exact same thing. How could I have been so thoughtless?

But suddenly, she’s leaning in toward me, eyes wide. “You shouldn’t let anything hold you back,” she says. “When you work out what it is you need to do, you have to go for it, one hundred percent.”

“I was going to apply to do an English degree at Greenwich University.”

“So what’s stopping you?”