‘Oh, a couple of young lads and girls. Been climbing up the buildings and generally making a nuisance of themselves. We’ll catch them in the end, and then they’ll get sent down, and maybe they’ll even learn a lesson from it. I just hope we get them before they get themselves killed.’

I offered him a glass of water, which he took gratefully. He sat down in the chair by the bed, and it occurred to me that he was only a little younger than my own father, and quite old to be made to run up and down flights of stairs after privileged young students. The thought made me even less sympathetic to Michael, and I decided to tease out his purgatory a little more with a few questions.

‘Who’s doing it?’ I asked.

‘One group. We think there’re three or four of them.’

I was interested to hear that my guest was not alone, that he was part of a larger outfit. I wondered where the others were hiding.

‘Is it so bad, climbing the buildings?’ I asked him, sitting down on the edge of the bed. ‘I mean, do they damage anything?’

‘No,’ he said, ‘not damage exactly. But they do something. It’s no good, seeing people like that going all over the college, and everyone knowing about it.’

‘Why?’

He shrugged, as if it were obvious. ‘Sets a bad example. Can’t have things like that going unpunished. We’ve had more problems this term than we did last year, and that’s more than the year before. Most of it’s just high jinks, and we don’t mind that, high jinks, but there’re other things, fights and drugs and cheating and such . . .’ He trailed off glumly, as if contemplating an invincible host of evils. I could tell he was the type of man who enjoyed a good portion of doom, and his claims about narcotics and violence seemed ridiculous in the peace of the Cambridge night.

‘But you can’t put that down to people climbing buildings, surely?’ I asked.

‘Well, they’re a danger to themselves, and a danger to others,’ he said, ‘but that’s not it. A thing like that, it can upset the tone of the whole college, and people who do one kind of wrong will do another.’

I found this statement a little cryptic, and thought it might be some proverb conscripted to an awkward use. I decided to change the subject. ‘Why do they do it? The climbing, I mean?’

‘Couldn’t rightly say.’

I was beginning to regret having invited the man to stay. I was aware that, though I had not lied to the porter, my silence would look like complicity, and so as he spoke I became more and more uncomfortable. Each passing moment seemed to increase the chances of Michael being found, and my guilt in concealing him grew. At the same time, however, I felt an uneasy fascination as I heard him speak. Each word seemed to open the door a fraction on to a shady world of midnight pursuits. Presently he relieved my dilemma as he rose and thanked me for the drink. He asked me how I was settling in to college, and I could see that his concern was genuine, for when he posed the question the slight fold of tension that had lodged between his eyebrows when discussing the chase smoothed away. He told me that I should come and see him in the porters’ lodge if there was anything I needed, and I was surprised to find myself touched by the offer. I realized at that moment how lonely I had become: isolation had worn away my resistance to small acts of kindness. He said he must be getting back to his duties. He explained that the night’s chase had begun when he had caught a glimpse of a man on the rooftops whilst patrolling New Court. I said goodbye to him, and wished him better luck in the pursuit of his quarry. He called me ‘sir’ when he said goodnight.