And as for that girl she had in tow, that grubby follower: I think Rachel was secretly grateful that I dispatched her. She seemed like the kind of character who would’ve had a ratty old sleeping bag stowed in her rucksack, all ready to set up camp on the sofa for the next ten years, not a penny paid in rent.

My composure dropped the second I got into the car. It was a stupid white SUV that Nick had bought us, the driver’s seat high up off the road as if that somehow made us all powerful. I dropped my head to the steering wheel and gave way to the sobs I’d been holding in for the past hour. The horn tooted as my head hit it, and I had a weird solitary laugh at the unbridled tragedy of my life. I looked up at the yellow glow of Rachel’s window, desperate to race back up the stairs and hold her in my arms, share the laugh with the funniest of my children. But this was like the naughty step – a necessary evil. She needed to feel the chill to come back into the warmth, once and for all. I hoped so, anyway. The anguished twist of her face when I’d left her had torn at my heart.

I had to do this. She was skirting far too close to the truth.

I wasn’t toxic, but our secret certainly was.

RACHEL

It was four in the morning by the time I fell into a sweaty, nightmare-ridden sleep, the alarm simply part of the hideous dreamscape. I punched it off, waking again at ten, and sitting bolt upright in horror. It was my first day back at work, and I was in my pyjamas mid-morning like a student. I took the world’s briefest shower, threw on a skirt with a crumpled shirt over the top from the bottom of the wash basket, and raced for the tube.

No one was in our section when I walked in, and I fantasized for one glorious moment that I had the day wrong, could turn around and go back to bed. But then I saw through the glass into the conference room. Heads were bowed, papers strewn across the table. Duncan looked up and saw me, his familiar look of disappointment replaced by something more worrying. Was it resignation? I half sprinted across the floor, my chest so tight I could barely breathe.

‘Sorry, sorry,’ I said. There was no chair for me, and I had to wheel one in, everyone stopping what they were doing to watch me, sweaty and stressed. Julia at least smiled at me, but it felt guarded, like she didn’t want to damage her own reputation by coming out as my friend. ‘Sorry again,’ I said, once I was sitting in the circle. ‘I had a family emergency. What have I missed?’