If Lisa had liaisons of her own, I did not know about them. She was an incredibly private person, and never offered her friends more than one perspective on her life. She distributed small slices of knowledge to different social groups, with associates among the students, the staff, local businessmen and regular visitors from London, taking great pains to ensure that none of these people ever met the others. It was part of her power that no one could really say they knew the whole of her, and I’m quite sure she could have concealed nymphomania and celibacy with equal ease. I had never met someone so capable of realizing their own desires, and I liked her, but she frightened me a little. Her rough London background was a constant reproach to the life we were leading, and to the family money that underpinned our leisure, but she never registered any envy or disapproval. She seldom made concessions in her clothes or manner; when she did, on the social occasions that required evening wear or elegant formality, Jessica was her pattern, and the attempts were never wholly successful. Her brown hair stayed scraped backwards in the resolute grip of a scrunchie. Unlike me and Jessica, who were entirely reliant on Francis, or Michael who had his own trust fund, she made her own cash, and probably earned considerably more in that first year in university than I did in my first year of law. Of all the group, she was the one I understood the least.

It was a cold winter that year in Cambridge: ice crystals glistened on the rough sandstone walls, and the trees over the Cam dipped snow-laden branches into the still surface of the frozen river. Every evening there were snowball fights in Market Square, big public battles that involved anyone willing to come out and scoop up a fistful of snow from the cobbles. It was after one of these late-night skirmishes that I first saw Francis’s room. My fingers were stinging and patchy red and white, and we were breathless with laughter and the cold. He asked me up quite casually, as he claimed he wanted to fetch a scarf and black shoes before we met the others for dinner, but as the invitation had never been extended before in the month or so of our friendship I could not help but see it as a landmark, a further pledge of trust, like an expensive gift wrapped in newspaper and left without ceremony on the kitchen table.