Meredith shook her head. ‘There aren’t any cameras in that part of the grounds. I’m sure there aren’t. We came down from his office the back way. He didn’t want the security guys to see us go in to the loo. Or risk doing it in his office, because they sometimes pop in for a chat if he’s working late … We’ll just say you came to meet me and we were having a walk because it’s such a nice evening.’

‘OK … but what about when the police find your DNA on him?’

Something else occurred to him, and he grimaced, pushing his sweaty hair out of his eyes. ‘Um … did you use a condom?’

Meredith hung her head, shamefaced.

‘Mez! That’s terrible! You should know better.’

She rolled her eyes. ‘Listen, you might have sex every other day, but I haven’t done it since Alasdair and I split up, and that was about four years ago! I didn’t even get that far with Gary. And Ralph is – was – a sixty-year-old married man. It certainly wasn’t planned, and I really doubt he’s been putting it about. Risking herpes is the least of my problems. It’s a good thing there’s no condom – less evidence to be found.’

‘Well I’m disappointed in you, sis. And I don’t know what you think I get up to when I’m not with you, because I certainly haven’t been at it every other day for quite some time. Promise me you will be safer in future.’

‘Whatever, Pete. It’s irrelevant anyway, because I am never, ever having sex again, as long as I live.’

They walked in silence back towards the ice house. Pete reached out for her hand, as he occasionally had when they were kids.

As they rounded the corner from the rose garden onto the sweeping back lawns, a cheery voice came out of nowhere, and Pete felt them both jerk with shock, as if there would be two more heart attacks in the grounds that night.

‘’Ello! Evening constitutional, is it?’

The owner of the voice was a portly, elderly man in some kind of dark-green uniform, carrying a huge torch, even though it was still light. He was almost as wide as he was tall, with a flat but bulbous nose that spread halfway across his face, like it was trying to escape.

Meredith dropped Pete’s hand fast, but stayed pressed close to his side, hoping, he could tell, that the man hadn’t noticed.

‘Pete, this is Leonard, our night-security guard,’ she said. ‘Leonard, my twin brother, Pete. You must have just come on duty?’

Pete was impressed at how normal she made her voice sound. But then she always had been good at hiding her real feelings from the rest of the world. Too good, often.