When Chris Bowden went to East Africa for his Duke of Edinburgh Award, little did he realise how it would change his life. Nick Morrison meets a teenager with a mission.

CHRIS Bowden still winces at the memory of how he let his class down. It may have been understandable, but he's still ashamed that, after two months of teaching, there was still something he never mastered.

"I never learned all their names. I hate to think about that," he says. "I thought 'I have come here to teach these kids, at least I should know their names'. But there were 76 of them."

His other class was much easier. It had just 54 pupils, although they too found themselves ten to a desk and sharing pencils. And keeping order in a class of 50 or more provides its own different challenge.

"In Kenya, the kids actively want to learn, especially the kids who have come from difficult backgrounds, who recognise it as a way of getting out of the cycle they are in. But there is always the trouble maker or a couple of kids who don't want to learn," adds Chris, 19.

"A lot of the time they're just kids. They're hard to settle down and they just chatter. It can be quite difficult to control, but a lot of the time they talk but still do their work."

Chris's stint at Wagai Primary School last summer was his third trip to Kenya, but the first time he had not been with other white people. The town of Wagai in western Kenya, a collection of concrete buildings with tin roofs and a tarmacked road running through the middle, has a population of around 700, and put him an hour's drive from the nearest white person.

"It can be a little bit daunting, although it never really causes a problem," he says. "When I got on the local transport - a minibus which seats about 14 people but is usually packed with about 30 - they would shout out 'mzungu', which means 'white people'.

"The further you are from the towns, the more often you come across people who have never met a white person, and little kids who stare and follow you as you walk. It is interesting to have the feeling that you're the first white person they have ever seen."

Chris, from Newton Aycliffe, first went to Kenya in 2001. For his Duke of Edinburgh gold award expedition, he signed up with Adventure Alternatives, a company which runs trips to East Africa. Adventure Alternatives works alongside Moving Mountains, a charity which works in developing countries, using expedition profits to fund its projects.

The four week trip, Africamp, sees the volunteers spend two weeks working - for Chris it was building a classroom in Kibera, a shanty town of around 800,000 people on the outskirts of the Kenyan capital Nairobi - then a week on safari and a week on Mount Kenya.

By the time he returned to County Durham, he was hooked.

"The first time I went out it was purely for me, so I could do my gold expedition, but once I had been out and seen those kids and seen another side to life, completely different to the life I knew, once I felt I had helped make an impact, it would feel wrong not to go back. It would feel like I was abandoning friends," he says.

"It is so striking a landscape and it has got wealth and shanty towns, and I feel like I'm making a difference."

Chris returned again to Kenya at the start of his gap year in 2003, and then last year, when he taught at Wagai. In July he goes back again for two months, but this time as an employee of Adventure Alternative, helping to run its camps.

This year, the tenth anniversary of its first expedition to Kenya, the company is taking out four groups. One will build a clinic for HIV positive children in Kibera, a second will build an orphanage in Wagai, a third will renovate the school in Wagai where Chris taught and the last will renovate a centre in Embu, central Kenya, where food can be stored, to be handed out in times of drought.

Chris will be involved in the projects to build the grain store and the orphanage.

"With HIV and Aids being a huge epidemic, there are a lot of children who have lost parents, and unless they have a family to support them, they will end up either trying to get to an orphanage, which requires money, or living on the streets and begging," he says.

"One of the kids we worked with, we found sitting on a rubbish tip in Kibera at the age of five. Her mother couldn't afford to support the family and the kids went out to beg, and when they couldn't get enough money this five-year-old prostituted herself to try and raise money. She started glue sniffing to take away the memories."

Camp life on the expeditions is fairly basic: cooking Kenyan food over a fire and with no electricity. When he was teaching in Wagai, Chris lived in a concrete house, with two rooms and a hole in the ground for a toilet, no electricity and no running water. Nightlife is limited to a bar, but no electricity means no fridge which means warm beer.

"It is quite difficult to adapt and can be quite a culture shock, especially for people coming out for the first time. When I was there teaching, it was quite isolated in that there is nothing to do and the nearest Internet is half an hour away," he says.

"It gets dark about 6.30pm and there is no light, just candles, so I would sit marking school books by candle. But for the camps we get a fire going and there are dances. East Africans love to dance, and we have to join in but it can be pretty embarrassing."

His experiences in Kenya inspired Chris, a former pupil at Woodham School, Newton Aycliffe, and Queen Elizabeth Sixth Form in Darlington, to study Swahili and development studies at the School of Oriental and African Studies in London, where he is now completing his first year. It's clear how deeply he's been affected, and how deep is the hold Kenya has on him.

"At first when I come back it is brilliant, it's home comforts and stuff you have been missing for two months. But a couple of weeks after that I will be dying to be back in Kenya, eating local food and living the way I have done. I hate coming back in a way; I could do with coming home for a week and then going back," he says.

"It means I've actually done something with my summer and I can come back reflecting on what has happened, as opposed to just coming back showing off a tan. It just means something to me. In the future I hope to do a lot more."