Honoured at this year's Encaenia for his achievements, Jimmy Carter shows no sign of slowing down. Interview by Greg Neale.

For a politician voted out of office more than 25 years ago, Jimmy Carter has enjoyed - is enjoying - a remarkably active 'retirement'. Since leaving the White House in January 1981, the 39th President of the United States has pursued multiple careers and numerous interests, and in his eighties is still making regular, often controversial, forays into the political arena. Perhaps it was as much for this continued activity as for his achievements as President that he received particularly warm applause in the Sheldonian Theatre in June when he received an Honorary Degree of Doctor of Civil Law.

The trademark Carter grin from the late 1970s is now more of a familiar, almost rueful, smile, but when we met in Mansfield College the day after the ceremony, his enjoyment of the experience was still very much in evidence. 'I think that among the honorary degrees offered in the world this is the pre-eminent one, and I will certainly cherish the honour and the memories of it', he said. 'It's been a delightful experience, getting to know so many people from different colleges and spending private time in conversation with the Chancellor and the Vice-Chancellor and other University leaders, so I think in every aspect it's been both a pleasure and very gratifying.'

Fittingly for a man whose first involvement in public life was on a local schools board, whose first campaigns for the Georgia State Senate were based on education issues, who in his inaugural presidential address quoted his former high school teacher, Julia Coleman, and then went on to set up America's first cabinet-level department of education, Carter has retained links with academic life. 'I've been a professor now for 25 years at Emory University [in Atlanta] and I know the pleasure I get in relating to the students on a continuing basis', he said.

Perhaps it is this involvement which leads him to endorse former students' continuing support for their universities, on either side of the Atlantic. 'There's obviously a limit on what a university can do out of existing funds or funds ... from the government or fees from the students and so forth', he said. 'Alumni contributions ... can be used in a very flexible way to expand the offering of the University, and to realise ambitions that the Chancellor or the Fellows cherish but don't have the funds to cover.

'Also, the rapidly changing technology in all kinds of research requires much more of a financial investment than has been the case in previous generations, when you could build a building and a chapel and a dining hall and some rooms for the students and you could go with that for hundreds of years. Now, life's changing, and I think that of all the benevolent causes that wealthy alumni can espouse, the improvement of their old university or alma mater is one of the most gratifying.'

Education clearly mattered for the young James Earl Carter. The future president grew up on the outskirts of Plains, Georgia, where his father was a peanut farmer. From the deeply rural environment of the segregated South, Carter drew lasting lessons that clearly still inspire him. 'My high school principal, whom I really cherished, said that one must accommodate changing times, but plead to unchanging principles. Miss Julia was the kind of school teacher who challenged all of us rural children. I grew up in a community called Archway, outside Plains; I didn't have any white neighbours at all - all my neighbours were black - but she made sure that school accommodated the unique characteristics of each student, then challenged us to take best advantage of it. She insisted that we learn about classical music and great paintings, we had to memorise the names of the composers and their music, and also she had a long list of books to read.'

One of those books is the subject of a Jimmy Carter legend, but - risking not only the story but the possible wrath of a nearby aide - I asked whether it was true that when, aged 12, he read War and Peace, he was disappointed to find Tolstoy's classic wasn't about the Wild West? 'Yes!' Carter laughed good-naturedly. 'Well, when I heard the name I thought it was going to be cowboys and Indians.'

There was another lesson to learn. 'As I said, I grew up in a community that had no white neighbours, all my neighbours were black, and I saw as I advanced in years the devastating affliction of racial segregation and also the self-imposition of affliction on the white oppressors. My mother ignored the mores and customs of racial segregation, and I think she planted in me similar feelings.' Carter's first political campaign, running for the Georgia State Senate, was in opposition to segregation in schools. When he became Governor - succeeding the segregationist Lester Maddox - he instigated an equal rights policy, appointing African Americans to posts from which they had previously been excluded.

Human rights was a theme that Carter took with him into the White House, after his image as an efficient, centrist-liberal Democrat governor from the 'New South' helped him beat President Gerald Ford in the presidential election of 1976, when America was seeking to come to terms with the Watergate scandal and the resignation of Richard Nixon. And although his single term was beset by domestic economic problems and - at its end - the crisis surrounding the seizure of the US embassy in Tehran, Carter now identifies human rights policies, at home and abroad, as among his enduring legacies. 'We did a lot of innovative things while I was President. We established human rights as a foundation for foreign policy; we got along quite well with the Soviet Union in the Cold War and we were able to bring peace - at least at that time - in the Middle East, and to normalise diplomatic relations with China.

'You know, we were able to meet all the challenges of the Cold War eruption of regional conflicts. I tried to weather those challenges and maintain peace at the same time and not endanger the integrity or the security of my own country, so I was glad that I was able to go through the four years and we'd never launched a missile or fired a bullet or dropped a bomb on anyone. And at the same time I think that there's no doubt that our espousing human rights as a top diplomatic commitment has paid rich dividends over the years. When I became President, almost all the countries in Latin America, certainly more than half of them, were dictatorships, military dictatorships. And over a period of years - not because of me but because of the policy - people began to demand their own right to choose their leaders.'

Carter admits his human rights policies were not universally welcomed, even among his then Western allies. His support for political dissidents in the Soviet Union is said to have helped many win the right to emigrate - there was a notable exodus to Israel - but some European leaders doubted its wisdom. 'I had some problems and altercations with some of the European leaders', he said. 'Helmut Schmidt [Chancellor of West Germany, 1974-82], for instance, thought that my human rights policy was completely fallacious because he thought we could accomplish more in changing circumstances in the Soviet Union by not confronting them forthrightly on human rights. But that was part of the changing times.'

Since losing the presidency, Jimmy Carter has still attracted critics for some of his political interventions, whether directly, or as a regular monitor of elections around the globe. He has met Cuba's Fidel Castro and Venezuela's Hugo Chavez, bogeymen for many American conservatives. A committed Christian, he has criticised the influence of the religious right in US politics. He has angered many supporters of Israel by his support for Palestinian rights, which he argues should include a return to the borders existing before the sweeping Israeli gains in the 1967 Six Day War, and he has most recently been an outspoken critic of both President George W Bush and the former UK Prime Minister Tony Blair - in his last days in office at the time of this interview - over the invasion of Iraq.

'I thought before, during and since the Iraqi invasion that it was completely unjust and unnecessary; it was implemented on the basis of false premises or deliberate, misleading statements, and it's turned out to be a tragedy', he said. 'I don't criticise his integrity or his honesty, and in fact I admire him in many ways, but I think had the Prime Minister strongly opposed some of the ill-advised decisions made in Washington, it would have made a difference.'

Many of Jimmy Carter's continuing initiatives have their home at the Carter Center in Atlanta, set up in 1982 with his wife Rosalynn to further his political interests, whether in medical aid for the developing world, human rights or furthering democratic institutions. While he still keeps an eye on the farm, he also travels extensively, has written prolifically, speaks regularly and even won a Grammy for the recording of one of his books. What, I wondered finally, still makes Jimmy run?

'Well I've been fortunate with my health, and we have very challenging and interesting and gratifying projects. One thing that the Carter Center has adopted from its initiation is to fill vacuums in the world, and there are a lot of vacuums in the world. We deal with diseases that are almost completely unknown in the rich world - onchcerciasis (river blindness), dracunculiasis (Guinea worm), lymphatic filariasis, trachoma, schistosomiasis and those kinds of things. So to go into the most remote villages in Africa and teach people how to alleviate their own suffering is exciting and it's adventurous and it's unpredictable, but it's very gratifying to me. It's not a sacrifice, you know, it's an opportunity.'

Details of the work of the Carter Center can be found at www.cartercenter.org and of the Carter Center United Kingdom at www.cartercenter.org.uk.