In his own words, he was "irrevocably betrothed to laughter", and rarely missed an opportunity to perform. As tributes pour in for one of Britain's best loved actors, and a multi-talented genius, Nick Morrison looks at the life of Sir Peter Ustinov.

IF ever anyone deserved the title of Renaissance Man, it was Sir Peter Ustinov. According to his biographer, he had enough careers for about six other men: Oscar-winning actor, Oscar-nominated screenwriter, a winner of three Emmys and a Grammy, an acclaimed director and writer and a goodwill ambassador for UN children's charity Unicef, with a genuine passion for promoting tolerance and understanding. He was a true citizen of the world.

But for many people, his most endearing role was none of the above - instead he was loved for those qualities which, to Michael Parkinson, made him "God's gift to the talk show host". A wonderful raconteur, he had a gift for storytelling, whether to a small group of friends or to a television audience of millions. As lightweight a talent as it may appear when set against his many others, it was as a teller of tales that Sir Peter became one of the most cherished figures of his and succeeding generations.

Sir Peter, who died of heart failure at a clinic near his home in Switzerland on Sunday night, was born in London on April 16, 1921, two months after his artist mother arrived from St Petersburg to be with her husband, a journalist. He was later to make great play of his cosmopolitan background, claiming to have Swiss, Ethiopian, Italian and French blood - seemingly everything, in fact, except English. He noted proudly in his autobiography, Dear Me, that he was conceived in Russia, baptised in Germany and brought up by nurses from Cameroon, Ireland and Germany.

His gift for mimicry first surfaced as a child, when, as a four-year-old, he would impersonate approaching cars, then watch pedestrians dive for cover on hearing the imaginary vehicles.

After Westminster School, he enrolled at the London Theatre Studio and became a professional actor at 18, writing his first play, House of Regrets, a year later. As the play transferred to the West End, Sir Peter joined the Army, where he was batman to David Niven.

He spent most of the war with the Army Cinema Unit, appearing in recruitment films, also giving him the opportunity to write and act, including acclaimed war drama The Way Ahead, which he co-wrote. After the war, his career took off, and in 1951 he won a Golden Globe as best supporting actor for his portrayal of Nero in the film Quo Vadis, a role for which he was also Oscar nominated.

HE went on to appear in a total of 90 films, and twice won the Oscar for Best Supporting Actor, as the slave owner Batiatus in Spartacus (1960), and as Arthur Simpson, a small-time profiteer who gets caught up in a jewel heist in Topkapi (1965).

Sir Peter put his talent for accents to good use in playing Agatha Christie's Belgian sleuth Hercule Poirot, in 1978's Death on the Nile, reuniting him with Niven, and giving him a role he went on to reprise several times, in Evil Under the Sun in 1982, Murder with Mirrors (1985) and Appointment with Death (1988). His film credits also included One of Our Dinosaurs Is Missing, Logan's Run, and Lorenzo's Oil.

He had a similarly illustrious television career, winning Emmys for playing Samuel Johnson in Dr Johnson, Socrates in Barefoot in Athens and a Jewish delicatessen owner in A Storm in Summer, and appearing in the TV films Jesus of Nazareth, The Thief of Baghdad, The Old Curiosity Shop, and as the Walrus, opposite Pete Postlethwaite's Carpenter, in Alice in Wonderland, among many others.

His success as an actor did not prevent him making his mark in other areas. His play The Love of Four Colonels was a hit both in the West End and on Broadway, Romanoff and Juliet was turned into a Hollywood film, and Halfway Up the Tree and Beethoven's Tenth were great triumphs. His screenplay for Hot Millions, in which he also starred, was nominated for an Oscar, and he won a Grammy for his narration on Tchaikovsky's Peter and the Wolf.

But it was away from performing that Sir Peter made perhaps his greatest contribution. For more than 30 years he was a goodwill ambassador for the United Nations Children's Fund, and took his responsibility seriously, travelling the world to promote Unicef's work and deeply sensitive to the injustices of the world. Even in his later years, wheelchair bound and hampered by sciatica and diabetes, he insisted on turning up for Unicef events, and he set up a foundation dedicated to promoting understanding between people in different countries and across different generations.

"I think knowing people is the best way of getting rid of prejudices," he said in 2001. "When I was young, I was brought up in an atmosphere which was just loaded with prejudices.

"When I came into my first classroom at the age of six there was a large oleograph of Jesus Christ holding a boy scout by the hand and pointing out the extent of the British Empire on the map. As a small foreign boy, I was outraged by this."

DESPITE his infirmities, Sir Peter took the same approach to old age as he took to most other things in his life. In an interview in 2001, he complained that advancing years meant he could not play tennis any more. "I see the ball coming and I think to myself, 'I have plenty of time to reach that', and it bounces three times before I've fallen down," he said.

In 1990 he was knighted for his vast mountain of charity work, but instructions for the ceremony at Buckingham Palace left him in a quandry. "The invitation said, 'Delete whichever is inapplicable: I can kneel/I cannot kneel', but there was nothing for those who can kneel but not get up," he remembered.

He remained active until shortly before his death, appearing as himself in the TV movie Winter Solstice last year, and he was a diligent Chancellor of Durham University. His BBC series Peter Ustinov's Russia involved travelling more than 100,000 miles to visit 30 cities.

His mischievous wit, seeming inability to take himself seriously, and a bottomless fund of stories made him one of the most popular guests on chat shows, where he could be relied upon to entertain, and for many, his funniest role was not in one of his vast store of films, but as himself.

Three times married, and the father of four children, Sir Peter made his home in Switzerland, perhaps appropriate for someone who considered themselves an international citizen. Fluent in French, German, Italian, Russian and Spanish, he could also get by in Greek and Turkish, and had a love of learning and culture which respected no boundaries.

Sir Peter claimed he was a serious person who happened to see the funny side of situations, but he believed humour was for more than just performance: it could be used to bring people together. "I was irrevocably betrothed to laughter," he once said. "The sound of which has always seemed to me the most civilised music in the world."