Keep the Lord always before you.' That was Eldryd Parry's answer when I asked his advice for today's junior doctors. I had expected him to talk about a global perspective, or serving the poor, or the importance of teaching. All of these came up in our conversation, but his first words to today's doctors were about priorities in our Christian lives.

'My worry about the church today is that Christians seem to be less distinct – their habits seem no different from everybody else. Take Bible reading. A survey done in a popular local church not long ago found that only a small percentage of the members read their Bibles regularly. I don't know how that's possible – how can faith grow unless it's built on daily prayer and Bible reading? I remember a story about Charles Simeon, a minister in Cambridge in the late eighteenth and early nineteenth century. He often found it hard to get up in the mornings, so he decided to give a guinea to his bed-maker every time he overslept. He soon found he was making the bed-maker rich! So he decided to throw the coin into the river instead. He soon stopped wasting his money and started to be disciplined in his Bible reading. He was greatly used by God.'

Professor Sir Eldryd Parry, KCMG, OBE – to give him his full title – has made a unique contribution in the world of global health. Between 1965 and 1985 he worked in five medical schools in Africa. On return he founded the Tropical Health Education Trust (THET), pioneering new approaches to medical education in developing countries. He planned and edited the seminal textbook, Principles of Medicine in Africa, now in its fourth edition.

However, he is a humble, approachable and encouraging man. I first met him while I was doing a course at the London School of Hygiene and Tropical Medicine. I was getting married a week after the course finished and setting off to work in a rural mission hospital in Zambia three weeks later. I told him that friends were concerned about us going away to such a remote place so soon after getting married. 'People can be so boring!' he said, 'I think that's a splendid idea.'

Medical schools in Africa - a new approach to teaching

His life has certainly not been boring. As a junior doctor, he was offered a one-year secondment to Ibadan, Nigeria, and stayed for two and a half. After finishing an MD thesis in London, he was invited to return to Africa to teach Ethiopia's first ever medical students at the University in Addis Ababa. This was the start of 20 years of uninterrupted service in Africa, which later took him to Zaria, then Ilorin in Nigeria and finally Kumasi in Ghana. 'At the beginning, I was just part of a team doing conventional medical teaching. Then in Ethiopia, I had the chance to shape the medical school, and we started doing new and innovative things – getting students into the community, introducing problem-based learning, and trying to relate everything to the needs of the local population. Education should be about stimulating students and bringing out their gifts – getting them to want to learn, rather than teaching them.'

'We didn't realise it at the time, but the experience we had in one place would equip us for the next. At the beginning of each year we would read, as we still do, Deuteronomy 8: "You shall remember all the ways the Lord your God has led you these 40 years. Your feet did not swell and your garment did not wear out." What a beautiful medical metaphor – it's talking about "famine oedema", how God led and provided for his people, just as he has done for us.'

On return to England in 1985 he worked for the Wellcome Trust, creating learning programmes for rural medical officers in Africa. 'I would ask them what they wanted – what they needed in their situation – and they told me. As I travelled around, I realised that Britain's historic responsibility for medical schools was being neglected. After the Second World War, the Inter-University Council for Higher Education Overseas was set up to help new countries build universities. But in the eighties the focus was on primary care – the ink was still drying on the Alma-Ata Declaration – and nobody wanted to know about medical schools. It was a time of great difficulty in Africa – the main streets of Kampala were full of potholes – and when I visited medical schools, I saw no books and no teachers, I saw no interest from Britain, and this was wrong.'

THET - a new approach to aid

Out of this concern for medical education came THET, which became a registered charity in 1989. Initially focusing on facilitating postgraduate training for key individuals, THET has supported over 200 partnerships around the world, linking health institutions in the UK with counterparts in developing countries. Eldryd explained: 'The pattern of aid has so often been "we know what is best, this is what we'll do for you, take it or leave it." THET's philosophy is about responding to what a country identifies as its need. We ask the question "where are you wanting to go and how can we help you to get there?" People were amazed: "We've never been asked what we want before. We've always been told what we need!" At THET we talk less about needs and more about opportunities. Rather than seeing pictures of starving children, we see a vision of people waiting to be trained so they can do a job.'

A new approach to mission

I asked Eldryd about the contribution Christians can make overseas. 'I thought I'd be a missionary doctor – everyone did – and my closest friends went overseas as missionaries. But when I wrote to a mission society they weren't interested in me as they didn't feel I had a strong enough "call". The opportunity for Christian health professionals is as great today as it ever has been, but it may be in a variety of different models, often expressing faith in a secular context. Mission hospitals make a great contribution, but they need to operate in conjunction with governments. There are huge opportunities with people at the margins. For example, there's an enormous slum on the edge of Nairobi. Urbanisation wasn't an issue when mission hospitals began, but it is a big problem now – will the church respond? Again, we must consult with the government to find out if they have a plan, and see how we might fit in. Wherever we work, our motto must be "I am among you as one who serves".'

I returned to the subject of Eldryd's advice for today's junior doctors interested in global health. 'Professionally, they've got to be excellent. They should do what they enjoy and what they're good at. These days a postgraduate qualification is almost essential, in order to be able to train others. Take a long-term view; get some early experience by all means, but don't be like confetti, all over the place – get to know a country and stick with it. There's no denying it is difficult with today's rigid training programme. But I still meet wonderful people who say "Never mind what the postgraduate dean says, I'm going to have a go". Those are the people who will do much more with their lives than those who play safe.' Eldryd's own life has been a testimony to that.