It was about a fellow of Divinity called Matthew Noaks, who, in 1915, had declared himself a conscientious objector. At high table the day after he had officially missed his draft, a single white feather was waiting for him on the leather seat of his high-backed chair, and the maids, who had brothers and husbands in the trenches in France, served him last, after the most junior student in the hall, and pretended not to hear when he asked for wine. His undergraduates, who before had worshipped him, would not look him in the eye at his tutorial, and when he returned to his rooms that night, he found another white feather, slid between the pages of the book on his night stand. The next day the Masters of all colleges received an invitation to lunch on the green outside King’s Chapel. Dr Noaks was waiting there, and by one o’clock a great crowd of students, fellows and staff had assembled. In bare feet, in broad daylight, he tied a Union Jack around his waist, and began to climb the north-east tower. He made the 160-foot ascent in just over twenty minutes and, at the pinnacle of the topmost spire, bound the flag to the lightning conductor and watched it unfurl, before coming back down and walking off through the assembled crowd, returning to his lectures. The Master of King’s called out marksmen from the barracks at Grantchester to shoot away an ‘obstruction’ on the chapel spire, but when the men arrived, the Major informed the Master that no enlisted man under his command would fire upon the Union Jack, and he would personally horsewhip any that tried. The Master hired a steeplejack to climb the spire and retrieve the flag, and was told that the ascent was far too dangerous. The Master hired a contractor, and was told that there was not the manpower to build the necessary scaffolding, all the able-bodied young men having gone to France. The flag stayed flying on the top of King’s Chapel until Armistice Day, when Dr Noaks, by now the Master of Trinity Hall, climbed the building a second time and brought it down with him. No one ever called him a coward again.

Francis was a magnificent storyteller. He mixed words like an alchemist, turning base metals into gold.

I remember also the last climb we made, or perhaps I cannot forget it. It was the closest we ever came to being caught, and I suppose to dying, though none of us ever spoke of it in that way. We simply met at the Copper Kettle the morning after, each of us nursing our scrapes and hurts, and agreed to lay low for a while to let things settle. By the time the matter arose again, the night climbing season was over.

Francis did much of the research for the climbs we made ourselves, but there were certain things, such as the condition of the stonework on lofty spires, or the presence of handholds invisible from the ground, that he took from the work of our forebears. Night climbing was, I discovered, not our own invention: there had been another group of students in the sixties who had done something similar, and before them generations of young men stretching back into history as far as the buildings themselves. According to Francis there was, on a particular ledge near the topmost spire of King’s College Chapel, a line of pennies showing the years of each ascension that dated back to 1630, as proud and incongruous in that lofty place as a line of footprints on the moon.