When Alexander McLean saw the appalling conditions of an African prison on his gap year, he set up a charity to help. After winning an award for his achievements, he's intent on becoming a barrister.

Most students who do voluntary work in Africa during their gap year wind up in the likes of orphanages and schools. Not Alexander McLean. It was prisons that grabbed his interest and what he discovered shocked him so much that he started up a charity which aims to alleviate the suffering of the hundreds of men, women and children imprisoned across the sub-Saharan continent. Throughout his years studying a law degree at the University of Nottingham, he helped the charity flourish.

"It was when I was helping out in the main hospital in Uganda – bathing and feeding patients with HIV, Aids and tuberculosis – that I met prisoners for the first time," says McLean, 22. "One in particular was in a deep coma, lying in his own waste, still handcuffed to the bed, with the guard nowhere to be seen. I remember thinking that if they're treated that badly when they're sick, what are they treated like when they're healthy? So I visited Luzira Maximum Security Prison in Uganda to find out."

The prison, which was built to hold 600 inmates, actually held about five times as many, he says. "Typically a six foot by 10 foot cell might hold 10 inmates who were forced to sleep on the floor. It was here that I also discovered how African prisons are controlled by brutal regimes and gang rape is rife."

Meanwhile, in a youth detention centre in Sierra Leone, McLean found that most of the children, aged eight to 16, had committed crimes such as "causing a palaver" or loitering. "One 14-year-old was locked up with her baby, who was only a few months old."

McLean accepted he couldn't change everything about the African prison system. But he felt he could do something about the provision of hygienic living conditions, better healthcare, and basic educational services. To that end he returned to England to fundraise and through founding African Prisons Project, he has helped create libraries, undertaken extensive refurbishments and improved the diet and health of prisoners.

It is this, together with his work as a welfare officer for his student halls and as vice president of the Nottingham University branch of Unicef that helped earn McLean the title of Graduate of the Year 2007. As if these posts didn't keep him busy enough, McLean also worked as an auxiliary nurse and magistrate throughout his studies.

The Graduate of the Year competition, run by Real World magazine, in association with PricewaterhouseCoopers and Moloney Search, recognises that there is more to university than just academic achievement. Students are rewarded for extra-curricular activities, work-based or campus activities that demonstrate their attitude, energy and commitment while at university. For McLean, it was voluntary work, but it could also be through setting up a business, student union activities, environmental work or other contributions to society at large.

McLean admits that there weren't many hours left in his days at university. "I'm not the best organiser, but it helped that I didn't watch much television and that I was lucky enough to get good results in my degree work without putting in too much work," he says.

Having graduated this summer, McLean is now back in Uganda with six friends. "We have a lot of work on our hands. I'm using the £5,000 prize for Graduate of the Year to help fund some of this work and I'll use the rest for living expenses. While I'm here for this year, I have no other source of income."

Besides the prison work, McLean will be studying for a Masters in Criminology and Criminal Justice by correspondence. "Then, next September, I want to start the bar course to become a criminal barrister. When I reach that position, my aim is to spend the sum of my time working in Africa to represent people on capital charges who don't have any legal representation."

McLean says his visits to Africa have shown him how few opportunities some people have in life. "In turn, that's made me appreciate what I have available to me and I want to make the most of that," he says.

Law has always attracted McLean as a career. "When I was 10, I wanted to become a judge," he recalls. "Mind you, as time went on I became increasingly interested in medicine, especially when I visited the children's prison in Sierra Leone."

Having volunteered as a healthcare assistant since he was 16 years old at Trinity Hospice in Clapham – where he still does a couple of shifts a month when in the UK – he had his fair share of exposure to the field of medicine. "But as I got into my law degree – and also became a magistrate – I realised law suited me better and that a career in it would still enable me to make a big difference."

McLean's achievements have not been without their challenges. "I often find that being young makes people suspicious about what you are able to achieve and what your motives are. Then there are the senior prison officers who have a lot of power and who have tried to make life as frustrating as possible for me. But through perseverance and determination, you can overcome such things."

McLean's message to other university students is not to underestimate what they're capable of. "We think we don't have the time or don't have the money or are too young to bring about significant change. But if you are persistent and know exactly what you want to achieve, you can do it."

For more information, visit www.africanprisonsproject.com