Murray Argyle had extraordinary presence. He was a large, elderly man with thick white hair, fearsome blue eyes and bushy eyebrows. He was my biology teacher at Bradfield College, Berkshire, from the age of 13 to 18 and I found him inspirational. He was charismatic in a quiet way, a rather mysterious character who had served in the Navy before becoming a teacher and there were rumours about him having been torpedoed in the war. There seemed to be some magic about him.

I always wanted to be an explorer. My dad was a test pilot and he brought home all sorts of exciting things from Africa like a weaverbird’s nest and a stuffed crocodile, which fired my imagination. Most of the teachers, especially the art master, dismissed me as a dreamer, but Mr Argyle understood. Looking back now I think he had a soft spot for me, though I didn’t realise it then. I got the feeling that he put in a good word for me with other members of staff.

Mr Argyle could control a room full of boys with a look. When he walked in - always very slowly - there was total silence. He didn’t suffer fools gladly, yet he was never nasty to anyone. I always looked forward to his lessons and yet I was always slightly scared.

He brought lessons alive with his enthusiasm for his subject rather than by telling funny stories. When we were busy dissecting rats and worms he would say that your best tools are your hands. He even managed to make equations for photosynthesis and respiration seem interesting.

He had extraordinary confidence, which is one of the keys of charisma, and I think what I looked up to in him. He was someone I wanted to be. He was a teacher of the old school who knew the name of every one of the 500 or so pupils. You would find him in some remote playing field inspecting the pitch, jabbing at the turf with a walking stick, or stalking round the school late at night on his own picking up litter, which he loathed.

He was solitary, but also gregarious, always a little bit aloo from people and yet at the centre of everything. I think all the other masters as well as the pupils were in awe of him.

After I’d been at the school a couple of years I’d talk to him when I bumped into him in the corridors, often about my collection of insectivorous plants. He was instrumental in my development from a total dreamer to someone who by 18 was starting to get his act together and won a number of prizes for biology projects.

I told Mr Argyle about wanting to be an explorer and he helped me to realise my dream. I think I was the sort of pupil he liked to encourage, someone who wasn’t top of the class, wasn’t academically brilliant not a sportsman, but different and needed to be told or needed to feel that he could make a difference in the world.

The last time I met him was about four years ago when I went back to the school to give a lecture. He was quite doddery and I was flattered he had made a special trip to be there. I wanted to give him a copy of one of my books, but he made a great point of opening up his wallet and taking out a crisp pound;20 note and paying for it.

Sometimes when I am feeling very alone on one of my expeditions, I think of Murray Argyle. I remember at the end of one exhausting day, having walked 30 miles across the desert, bending down to clear up the rubbish round my campsite and having a little chuckle. I felt his presence, like a sort of guiding spirit.

1960 Born in Macclesfield

1980 Makes first expedition, to Costa Rica (while a student at East Anglia University)

1982 First solo trip, to the Orinoco river in South America

1984 First book, Mad White Giant, published

1990 Crosses Torres Strait in Australasia by canoe

1997 The Skeleton Coats, television series about his walk with camels across Namib Desert, is broadcast

1998 Edge of Blue Heaven, television series about his five-month journey with horses and camels through Mongolia, is broadcast

2000 Last of the Medicine Men published. Also made into television series

2001 Plans to trek through Siberia with huskies