I had a shower, shaved, selected my least crumpled shirt and, at exactly six-thirty, went up the little flight of steps and rang the bell, carrying my bottle. The dinner passed in an atmosphere of polite, smiling, rather bland cordiality which I’d get used to in time. Beth had smartened herself up a little, though she still wasn’t wearing make-up. She had changed into a black silk blouse and brushed her hair so that it fell seductively over one side of her face. But none of it was for me: I soon found out that she played the cello with the chamber orchestra of the Sheldonian Theatre, the semicircular building with the gargoyles that I’d seen on my walk. They were having their final rehearsal that evening and some lucky man called Michael was picking her up in half an hour. There was a brief, awkward silence when, assuming that he must be, I asked if he was her boyfriend. The two women exchanged glances but as my only answer Mrs Eagleton asked if I’d like more potato salad. For the rest of the meal Beth seemed slightly absent and in the end the conversation was entirely between me and Mrs Eagleton.

The doorbell rang and, after Beth left, my hostess became noticeably more animated, as if an invisible thread of tension had slackened. She poured herself a second glass of wine and for a long time I listened to her talk about her eventful, remarkable life. During the war she’d been one of a small number of women who entered a national crossword competition, in all innocence, only to find that the prize was to be recruited and confined to an isolated little village, with the mission of helping Alan Turing and his team of mathematicians decipher the codes of the Nazis’ Enigma machine. That was where she met Mr Eagleton. She recounted lots of anecdotes about the war and also the circumstances surrounding Turing’s famous poisoning.