He was at Nasa, designing instruments for detecting life on Mars, when he conceived the Gaia Hypothesis, which considers the biosphere as a single self-regulating entity.

His book, The Revenge of Gaia, is out now in paperback "I was expelled from my nursery school in Letchworth after only a month for attempting mass murder.

The teacher was showing us all the poisonous plants, and when she left the room, I tried to induce the girls in the classroom next door to eat the deadly nightshade. I was sent home and never went back.

"Then I moved to Brixton and went to a Church of England primary where the teachers were excellent. They taught me to read and write, and lots of other interesting things, too. It was an almost ideal educational atmosphere. I was too happy to go in for poisoning.

"Then my mother rather foolishly felt that I ought to go to a grammar school as soon as possible. At nine, I went to Strand Grammar, a rather bad school in the same road as my primary school. The quality of teaching was, with a few exceptions, very poor, but the boys were wonderful; we taught each other. The lesser grammar schools at the time tended to employ people who had poor Oxbridge degrees and no teacher training . . . and they swanned around in gowns.

"They tried to make it like a public school, which didn't make a lot of sense. It was good that it wasn't co-educational, as there wasn't that distraction, but we did have a short-sighted master who was nicknamed Sappho because the pubescent boys made love with each other during his lessons.

"I failed in English and French in the equivalent of GCSEs. Unless you got satisfactory results, you couldn't go on to the equivalent of Alevels, but I passed the 'London Matriculation' after a couple of months of swotting at home, and could go on to the sixth form, where I did physics and chemistry and pure and applied mathematics.

"We had the better teachers, and one was first rate but an anomaly: he wasn't from Oxbridge and had a PhD. I got distinctions in physics and chemistry and failed both the maths exams.

I'm dyslexic and hopeless at arithmetic, but nowadays I love maths as computers do all the hard arithmetic chores.

"I took a job as a laboratory assistant for a company where I learnt much more than I did later at university:

they taught me that you must never fudge a result, as people could lose their jobs, or even lives. They paid for my fees when I started evening classes for my chemistry degree at Birkbeck College, but told me that as soon as I got a degree there wouldn't be a job for me as they couldn't pay graduate wages.

"It went swimmingly, but at the end of my first year the war started and most of the colleges were closed. I spent two years at Manchester University, where I completed my degree. I got a 2.2, largely because I was lazy and found more interesting lectures outside the degree course: economics, history . . .

anything but chemistry.

"I got a job at the National Institute of Medical Research in London, where I sat next to a Nobel prizewinner on wartime firewatching duties, who would give me a 'brain dump' . . . that is, pass on everything he knew.

After the war, I took a PhD at London University on the work I had done at the institute.

"My father was a countryman, born in 1872, and he gave me a love of the countryside and ecology that has stayed with me ever since.

He didn't go to school at all.

Finally, he was sent to Battersea Polytechnic to learn reading and writing, and I still have his certificate of proficiency."