Jamie could. It was a soft, rhythmic banging, plus a creaking sound further in the background. Then he heard a human sound: a gasp. The banging increased in pace and volume, and the gasping sounds got louder. At first it was just woman’s voice, and then a man joined in with a deeper grunt.

‘Kirsty.’

Hearing his voice on the CD made him stamp on the brake. The car behind stopped just in time, the driver sounding her horn angrily. Jamie pulled over to the side of the road, out of the traffic. On the stereo, the gasping and groaning grew steadily louder. It was them. Making love.

They looked at each other in horror. Kirsty had gone pale.

‘Jesus Christ.’

He pressed stop and ejected the CD. He was going to throw it out of the window but Kirsty stopped him. She said, ‘We might need it. And I don’t want anyone else to pick it up and listen to it.’

‘They recorded us having sex. I can’t believe it.’

‘Jamie, it makes me feel violated.’

‘I know. When the hell was this made? It can’t have been last night. We were quiet last night, weren’t we?’

She nodded. ‘They must have already recorded this when they sent us the letter. Maybe we did make noise last night without realising it and they sent this as, what? A warning?’ She shivered. ‘I feel like I need a bath. It’s horrible. Horrible.’

‘What are we going to do?’

Jamie looked at the CD in his hand. He felt that awful sense of weariness weighing down on him. ‘I really don’t know. I guess we’ll have to talk to them. Fucking Lucy and Chris. Christ, I thought we were meant to be friends.’

‘There was no note with it?’

‘No.’

‘So we don’t know for certain it’s from them.’

‘Kirsty, it has to be. There’s nobody else, apart from maybe Mary, who could hear us having sex. Unless somebody stood outside our front door recording it on their phone or something. Which also brings Brian and Linda into the equation.’

‘That’s ridiculous.’

‘Exactly. So it has to be the Newtons. It has to be.’

Kirsty imagined them in the flat below, holding a microphone up to the ceiling.

‘So tonight, we’ll go and talk to them, yes?’

The thought made Jamie feel nervous. He thought about Chris’s physical strength, those muscles. But he couldn’t allow himself to be a wimp or a coward. The Newtons had invaded their privacy. They had made Kirsty feel violated, as she put it. Something had to be done. So he said, ‘Yes.’

‘Hopefully we’ll be able to sort something out sensibly, like adults.’ She sighed. ‘God, we really don’t need this at the moment, do we?’