Occasionally you think of something that you could have said, or should have said, or wish you had said, just a few seconds too late. I have had an example of this in my head for over 30 years now. It was at the start of my second year at university and followed on from something that happened the previous term.

In those days my old school sent enough students to Cambridge to have an annual dinner at one of the colleges for its alumni. There were around 15 of us in my year, maybe 50 undergraduates in all spread across the various years. There were over 20 from my old school about to sit their finals. Numbers for subsequent years rarely reached double figures. I had no intention of going to the Old School Dinner in my first year but one of my old teachers contacted me to say that I really should. I wasn’t interested. “You really should,” he said, “Because four of us are coming up and we’d like to stay in your room.” The four visitors were two of my former teachers and two students who were starting at Cambridge in October. I knew one of them, vaguely, but had never met the other one, didn’t even recognize him. (My school was like that, at least in my day: very little communication between years unless you were a keen sportsman.) The dinner was to take place during the weekend of the May Day Bank Holiday. I said okay, bought in extra supplies of gin and tonic and college port, and rearranged my weekend.

The meal was good, held at Trinity Hall, and I enjoyed seeing my old headmaster again. He mentioned me in his after-dinner speech, which was rather a shock, but I was the only undergraduate in the room who was reading History, and he had made a reference to the historical setting of “Vanity Fair”.

After the meal (a boozy affair, with plenty of drinks before, during and after) we headed back to my typically functional first-year room. Somehow four sleeping bags, with occupants, were able to fit across the floor, two by two in the space between the window and the wardrobe. I had my own bed, and slept like a log.

I woke before everyone else the next morning and reached for the book that I had hoped to read that weekend, “Ulysses”. I had started it on the Friday evening, made good progress, and thought that I might stay up most of the night, maybe even finish it before Saturday evening. As things turned out I did stay up all Friday night, diverted by a group of friends inviting me on a nocturnal punting party to Grantchester and back. We had rolled back into Trinity at 6am and I slept till lunch-time. “Ulysses” had remained untouched for nearly 36 hours until Sunday morning.

My room, understandably, did not smell especially pleasant. Five grown men had been to a big, boozy dinner and then shared a space intended for a lone undergraduate. My guests woke up during the next hour or two and I made breakfast. Not everyone was up for it. It turned out that one of the future undergraduates, the one I didn’t know, had been sick in the night, all over the carpet. The four of them had tried to clear up as best they could, using whatever towels and cleaning stuffs they could find, and they had managed to do this without waking me. And once I knew that the smell wasn’t just that of five guys in a small space it was hard to ignore. The four of them headed back to London soon afterwards. I tackled the carpet with soap and water, tea-towels and a sponge. I have never worn after-shave. If I had maybe I’d have had some strong-smelling male grooming product to hand to try and mask the smell.

I took a break from my time-consuming attempts to clean the carpet to attend a drinks party at noon. I told a friend about my night and morning. “The only way to deal with vomit on a carpet,” he told me with authority, “is TCP. The carpet will stink of TCP, forever, but it won’t smell of sick any more.” As you probably know, TCP is a very strong-smelling mouthwash and antiseptic. Its smell never disappears completely. He had a bottle in his room, he’d drop it over to me. Sunday trading was a very different business in the 1980s. There was probably nowhere to buy any kind of mouthwash, antiseptic or cleaning products until Monday morning.

That afternoon I doused the carpet with TCP, left the window open, and went to a movie. The prospect of staying in my room and reading “Ulysses” had been rendered much less appealing by the competing smells. Fortunately there were only six or seven weeks of term left, and the various smells diminished during that time. By June you could hardly notice them.

One afternoon in October, at the start of the following term, I was walking down Kings Parade with the same friend who had given me the advice about (and the bottle of) TCP. Someone I didn’t recognize came up to me and introduced himself. “Don’t you remember me?” he said. I didn’t. “I’m John.” Nope. “I’m the bloke who puked up all over your carpet.” Ah. I made some small talk, asking him what college he was at, introduced him to my mate, who knew all about the carpet incident. And what I wish I’d said, and it only came to mind when we’d gone our separate ways, was: “Feeling better now?” But by then it was too late.