The other women were on their feet, as if by some signal I couldn’t hear. I stood up too, painfully conscious of how much my shoes cost. As if they’d notice, or care. Oh God. I was sweating. My throat was dry. I felt trapped, even though when this was over I could leave. Jake couldn’t. We all shuffled into a line as the door opened, and a bored-looking female guard passed a wand over us. It was like the airport, only with less sense of urgency. I shuffled forward with my plastic bag clutched like a baby, having left my expensive handbag (£600) in a locker. The woman in front of me was wearing what looked like pyjama bottoms, printed over in puppies, and a sagging vest top showing her breasts, which hung down almost to her waist. Her hair was dyed with streaks of red and purple and she could have been any age. Thirty? Fifty? I was horrified by this place, and by my reaction to it even more. Her huge gold earrings set off the wand, and she was pulled to one side. I took her place, assuming I’d zip through as I always did at airports, and I actually jumped when the detector went off.

‘I don’t . . . sorry . . .’

The guard sighed, so disinterested she could hardly look at me, and patted me down. Under my arms. Round my breasts. Between my legs. It was humiliating, and I stood spread-eagled in my Toast dress (£160) and felt her rough hands roving over me, and I was horrified to find tears in my eyes. What would Karen say? She’d be disgusted with me. She must have been here so many times already, despite living miles away, despite having no car. There was no way she’d leave her boy in here alone. She’d done everything she could for him over the years – working for idiots, grinding her teeth and getting on with it, demanding the extra funding at his school and the tutors and the support. Fighting to keep him in his father’s life, even though no one but Karen knew it. I used to admire that. Before I knew I was the duped wife in it all.

I wasn’t going to think about Karen.