It’s twenty-five years this month since I started at Downing College, Cambridge. I can scarcely believe it possible. The calendar used to be so friendly, and now it mocks me.

My route to Cambridge was unorthodox. I had my A-level results before I applied, and so my admissions interviews the previous winter covered slightly different ground than those of others, I suspect. I already had the grades they wanted: Downing had to decide whether to make an unconditional offer, or reject me.

I remember it as a dark, gloomy Friday in December, and I remember me as a bag of Tesco’s Finest nerves. I had three interviews that day: one with the senior tutor, one with the Director of Studies of the course I’d applied for (computer science), and one with a physics professor.

The latter might seem odd: after all, computer science is a few levels of abstraction away from physics. But Cambridge doesn’t like you to specialise on a science too early. In year one, should I be accepted, I’d be following a curriculum mixing computer science with both maths and physics.

I hadn’t twigged, naive hair-headed youngster in ill-fitting suit that I was, that the physics professor would ask me physics questions. I suppose I thought he was just a second or third opinion, since I’d already proved my knowledge in the subject under exam conditions a few months before (A-level grade A, S-level grade 2, if you’re counting). Thus, on entering his wood-panelled office and spotting what looked like a delicate windmill in a crystal ball on his desk beside a standard lamp, I began to worry.

The funny thing about subjects you don’t think you’re going to study again: as soon as you finish your final exam, all knowledge drains out of your brain.

We had the usual warm-up chat, with a few opportunities for me to burble away my nerves. All the while I was giving sideways glances to the ball and hoping it was decoration, a talking point, a physics professor’s equivalent of an Afghan rug on the wall.

It wasn’t. When the moment arrived I dredged up enough discarded theory to hum and haw my way towards the answers he wanted, and I remember leaving the interview distinctly more jelly-legged than I’d gone in. By then it was late, dark and cold, and I was glad it was my final interview of the day.

Earlier in the afternoon — after a college lunch, I think — I’d been to see my putative Director of Studies, Richard Stibbs. I sat outside his office with another candidate, who went in first. When my turn came, Mr Stibbs invited me in and asked me to take a seat.

Before me: a standard-issue wooden chair; a plush chair beside his desk, significantly more comfortable; and a small sofa, on which he sat with his notes and a copy of my application form.

Where would you sit?

I chose the chair beside his desk. I see it in exaggerated form even now in my mind’s eye: golden upholstery, inviting, empty. Begging me to sit on it.

I was supposed to take the boring wooden chair, of course, and Mr Stibbs said as much. I offered to move; he said it was fine.

I thought I’d made a tremendous faux pas. In retrospect I wonder if it helped — if it made me more memorable a candidate. Perhaps, although I reckon I was memorable enough as it is, applying post-A-levels. Having said that, when I arrived in October 1988 as an undergraduate, he did mention it to me. Ah, yes, you sat on my chair.

Sadly Richard died a few months ago, just short of retirement, after a career at Downing  and the University in various senior roles. At his death he was President of the College.

In 1988, he was younger than I am now. Damn calendar.