Asked to consider what he thinks has been his most significant achievement as an arts benefactor, former GP Dr David Cohen pauses for a moment before choosing his answer carefully. Then, without a shred of pomposity or fanfare, he explains that he has actually just returned from the launch of New Music 20x12 - a programme designed to put new music centre stage of the London 2012 Cultural Olympiad. "We're doing something which I think is giving us a feeling of satisfaction," he says.

New Music 20x12 was an idea initiated 18 months ago by Cohen and his wife, Jillian Barker. It arose out of a discussion, he says, "about the Olympics and what legacy it would leave. We thought that over and above the sporting legacy, if any, there ought to be something cultural to mark 2012. We played around with the figures '2012'; I was thinking about commissioning a piece of music for the year 2012. But as we were talking we both thought of the idea at about the same time."

What they came up with was a plan to commission 20 pieces of original music, each lasting 12 minutes. They went to the Arts Council and from there were introduced to the Performing Rights Society for Music Foundation and to LOCOG (The London Organising Committee of the Olympic Games). With the additional help of friends, they managed to raise £200,000. A committee was set up with the three organisations, as well as the BBC, to decide on who to commission. The names of the 20 artists are due to be announced today, with musicians of the calibre of jazz pianist Julian Joseph and Scottish composer Anna Meredith expected to be involved.

At 81, Cohen remains one of Britain's most active cultural philanthropists. He has served on the boards of many of Britain's finest institutions, such as the Royal Ballet Schools, the Royal Opera House and the National Theatre Development Council. Current commitments include the Royal Philharmonic Orchestra Trust. It is no surprise that he was awarded a CBE in 2001 for charitable services, especially to the arts.

His motivation is simple. "I love all the arts. I couldn't imagine a life without music for instance. One of my early ambitions as a schoolboy was to be an architect. In fact, when I was about nine or 10, I wanted to go to art school. My parents were not impressed. They felt I should get a good education first."

We thought that there ought to be something cultural to mark 2010

This good education included a degree in Oriental studies at Oxford and then being awarded a Fulbright Fellowship to study mediaeval Jewish philosophy in the United States. He qualified as a doctor from Westminster Hospital, working in general practice, which he says he "enjoyed enormously". He retired from medicine in 2001.

His career in philanthropy started back in 1965, when together with his father, John S Cohen, he and his mother and brother set up the John S Cohen Foundation. "My father, having left home at 15 without much formal schooling, was quite passionate about education so in the early years this was the trust's strongest interest," he says. Much money was given towards Jewish causes, in particular to the Hebrew University. (Cohen says of his Jewishness now: "I've become totally non-practising as a Jew. I don't go to shul.")

Later, the foundation merged with the David Cohen Family Trust (founded by Cohen in 1980 with his then wife, Veronica). The trust, which deals with around 3,000 requests for money a year, focuses on education, conservation, environment and the arts, including the David Cohen Prize for Literature, a £40,000 biennial prize that was established in 2002. It honours a living writer, from the UK or the Republic of Ireland, for a lifetime's achievement in literature. The last recipient was Seamus Heaney who joined a distinguished list including V S Naipaul, Beryl Bainbridge and Michael Holroyd. "But," adds Cohen wistfully, "we've missed a lot of great writers, who have been in contention and died before the end of the process." The winner of the 10th prize will be announced in March 2011.

He does admit to being embarrassed that the prize is in his name. It had not been his wish but "the one who pressed for it was P D James. She spoke so forcibly about it, I let it go," he says.

Unlike the Man Booker Prize, there is no shortlist. "We think it's invidious that somebody should be on a list and drawn to the public's attention that they're not the best. We are low key, discreet," he explains. Whatever his opinion of published shortlists, he is "very pleased" about Howard Jacobson's recent Man Booker win.

"I've enjoyed reading and listening to him," he says.