I have been very fortunate because my life has been full of great mentors, from Trevor Huddleston, the Bishop of Stepney, who encouraged my songwriting, and Anna Scher, who gave me the confidence to perform, to Bill Hinds, a great maths teacher who got me through my maths O-level a year early and made school fun. And then there was Jon Townsend, my economics teacher, who took a bunch of us on a trip to Derbyshire and opened my eyes to nature. I have had a love affair with mountains ever since.

I was a working-class kid from Islington and walking in the hills, certainly in the south of England, is a very middle-class thing to do - the nearest we ever got to the countryside was Finsbury Park or seeing a few cows on the way to Southend. However, when I started at Dame Alice Owen’s, which at that time was a grammar school in Islington - although it later became a comprehensive and moved to Potters Bar - I was introduced to a whole new world of middle-class pursuits.

Jon was a lean, athletic, good-looking man and I can still picture him striding purposefully ahead of me. He was very engaging: he had a soft way of speaking that drew you into him.

One of the things that impressed me about him was that he was physically strong without being macho - he managed to combine the athletic with the aesthetic. He made us understand that climbing and hill-walking weren’t just sporting activities but that they gave you a connection to the earth that you don’t get in a city.

The oldest building in a city will be a few hundred years old, but mountains have been there for millions of years and you are a dot on the landscape, so they give you a terrific sense of proportion. They are also humbling, because being out on the hills in stormy weather is extraordinarily dangerous so you have to keep your wits about you, but at the same time you are conscious of the beauty surrounding you.

After the first trip to Edale, I think Jon took us to the Lake District, and in 1977 I was awarded a travel bursary to climb Mount Toubkal, the highest mountain in north Africa. After a weekend training in the snow in Snowdonia, I flew to Morocco with Jon, two other teachers and two more pupils. I will never forget triumphantly standing on the top of that snowy African giant, 13,671 feet above sea level.

Jon taught me a lot of survival skills for severe weather, such as how to use an ice-axe. He showed me how to use a compass and cook on a camp stove - my wife laughs at me because I’m not very practical around the house, but when it comes to stuff like that I thoroughly enjoy it. He also introduced me to the beauties of an Ordnance Survey map and to (Alfred) Wainwright, who drew all those wonderful maps and illustrations of the Lake District, and with whom I have become obsessed.

I talked a lot to Jon as we walked the hills and he would explain the different rock faces and formations and the paths of least resistance. There was a group of us who got quite close to him. We got to call him by his first name out of school, but the relationship we had on our trips to the mountains never came into the classroom: I was treated like everyone else.

I got an A for my economics O-level - the only A I got - which must have been partly because I felt so comfortable and inspired by him, but I wasn’t as good a pupil in his classes as I might have been.

I still love climbing peaks and I have passed this passion on to my son, Finlay. Young boys don’t see the point in walking long distances, but they completely get the challenge of climbing a mountain.

By the time he was 10, I had taken Finlay up all the major peaks in Britain and more recently he has climbed Kilimanjaro and Mont Blanc; I’m hoping to inspire my two youngest to do the same.

Jon now lives in France with his wife. I got in touch with him last year when I was writing my book and we have made tentative plans to visit each other, which I’m very much looking forward to. I will always be grateful to him for being the first person to take me to the mountains.

Gary Kemp was guitarist and songwriter for Spandau Ballet. His autobiography, `I Know This Much: From Soho to Spandau,’ is out now in paperback. He was talking to Hilary Whitney.