I went to Radley College just outside Oxford. I enjoyed the school, but never in my wildest dreams would I send my children to it. It is there that I met David Goldsmith, a maths teacher. He was brilliant. He was one of those truly eccentric Englishmen, in the nicest possible way. He called everyone by their names spelt backwards, so I was always Htims Droffats Evilc to him.

He went around school looking like the archetypal crumpled British teacher in a shabby plaid jacket and knitted woollen waistcoat, saying “Heps Poon Choops” all the time. No one knew what it meant.

He also inverted the letters of the word boy, calling everyone “yob”. I remember him continuously calling one boy “yob”, and eventually he threw a duster at him, but no one disliked Mr Goldsmith or found him irritating.

He would stand at the front of the classroom in his jacket and black gown, chin pointing towards the ceiling, eyes firmly closed, rattling off numbers at great speed (9 x 7 + 2, 5 x 12 + 13 etc). He would go on for minutes and we had to write down the correct answer at the end. My brother Mark and I were maths swots, so we enjoyed the challenge.

Mr Goldsmith also taught the bridge club, of which I was a member. I remember him teaching us amazingly elaborate cheating systems, including one mysteriously called Budapest 123. I think he may have even given us a little glass of sherry when we came to play.

When he took us away on bridge tournaments, he would use our real names. That’s when I thought he must be fond of us bridge players. I still don’t know if he particularly liked me, but I had a real soft spot for him.

I can’t remember talking in much depth with Mr Goldsmith, but I imagine he was very intelligent - the sort to finish The Times crossword five minutes after breakfast. The fact that he was an inveterate fan of Ipswich Town Football Club also enamoured him to me. While they were my local team at home in East Anglia, he was a member of an elite group in faraway Oxfordshire. He and I were one of the very few Tractor Boys - Ipswich fans - at Radley. Mr Goldsmith would come in on a Monday morning to face the music about the latest disaster that had happened to his beloved team, while I would be demurely supportive.

He was a good maths teacher and I was a good pupil, choosing to do maths and the sciences in the sixth form - subjects I’ve found completely pointless ever since. I haven’t used anything I learnt from maths or science for the past 30 years. I needed something more human.

I’ve heard people talk about Mr Goldsmith, but I haven’t seen him since I left school. He must have been in his late forties and a confirmed idiosyncratic bachelor, but I heard he ended up marrying a secretary at the school. I would like to see him again. He was always excellent company.

Clive Stafford Smith is a civil rights lawyer and founder of Reprieve, a charity that provides legal support for prisoners on death row. He also defends British detainees at Guantanamo Bay. He was talking to Hannah Frankel. www.reprieve.org.uk.