ALISTAIR Cooke, the doyen of broadcasters who built a bridge of understanding across the Atlantic with his Letter from America, has died aged 95.

Age and ill-health finally caught up with him earlier this month when he announced his retirement after nearly 60 years of his much-loved weekly radio programme.

Those 15-minute personal reflections touched on everything from the Kennedy assassinations to the September 11 terrorist attacks. It was Cooke's ability to give his own twist to events, from the momentous to the mundane, that kept generations of listeners captivated.

Towards the end, he disliked the fact that the advancing years had reduced him to a frail, stooped figure. He did not like being old and confined to his 15th floor apartment on New York's Fifth Avenue, albeit a home with a stunning view across Central Park. It was there that he died, almost on the stroke of midnight on Monday.

No cause of death has yet been disclosed but Cooke recently revealed he was suffering from heart disease. After finishing his broadcasts in the months leading up to his final ''letter'' he would collapse, he said. He simply felt that he was not ''up to it'' any more.

''I've been feeling low for about two months. When I'd done my talk I used to collapse. I began to wonder if I could go on and I can't,'' he said.

Nick Clark, his close friend and biographer, said yesterday: ''I think he thought retirement was a very bad idea and when he was forced to stop work three weeks ago, I thought, this won't be long now, because here was a man living for this one task.''

Leading the tributes to this remarkable man, Tony Blair, the prime minister and a Cooke fan, said of Letters From America: ''I thought they were extraordinary essays and they brought an enormous amount of insight and understanding to the world. He was really one of the greatest broadcasters of all time, and we shall feel his loss very, very keenly indeed.''

On behalf of the veteran broadcaster's adopted country, William Farish, the US Ambassador to Britain, said: ''For many Americans he will always be associated with the best of Britain. He had movie star good looks, a poised and effortless manner, a first-class mind, and - most flatteringly - a sincere and abiding interest in all things American.''

Letter from America, broadcast on BBC Radio Four and on the World Service, started in 1946. Originally planned to run for just 13 weeks, it went on to become the world's longest-running speech radio series. In all the years it was broadcast, Cooke missed only three programmes. On one occasion, he produced the show from his hospital bed.

His unerring eye served to pinpoint the idiosyncrasies of the USA to a British audience which, over the years, amounted to millions.

To Americans, the silver-haired gentleman appeared to be the quintessential Englishman as he helped explain the eccentricities of his native land. His voice, that calming, gently insistent, elegant tone touched with the lilt of a transatlantic accent, was his trademark.

Born Alfred Cooke to working class parents in Salford in 1908, he gained an honours degree in English from Cambridge. When, in 1932, he came to the United States to study at Yale and Harvard, he took the opportunity to travel across the country by car. It was the start of a beautiful friendship with a foreign land.

''That trip was an absolute eye-opener for me. It truly changed me,'' he recalled.

Returning to England, Cooke joined the BBC in 1934, first as a film critic. He later became the London correspondent for the American NBC network.

In 1937 he went back to the USA as an immigrant, becoming a naturalised citizen in 1941. Four years later he was signed up as a correspondent for The Guardian and continued working for the paper until 1972.

In 1946 he started his weekly talk, then entitled American Letter (it was changed to Letter from America in 1950).

Over the years Cooke wrote a dozen books, including Alistair Cooke's America (1973) which sold more than 800,000 copies in hardback alone.

He was host of the landmark Omnibus television programme in the United States from 1952 to 1961, and presented Masterpiece Theatre on the US PBS network from 1971 to 1992.

He received four Emmy awards, three George Foster Peabody awards for broadcasting, and he was given an honorary knighthood in 1973.

Mark Byford, the BBC's acting director general, described Cooke as ''the outstanding commentator of the 20th century. His insight, wisdom and unique ability to craft words enabled millions of listeners in the UK and around the world to understand the texture of the United States and its people,'' he said. ''All of us at the BBC today are very sad to hear of his death.''

Jenny Abramsky, the BBC's director of radio and music, said: ''Alistair Cooke was the most brilliant radio chronicler of his age. His contribution to BBC radio was unmatched and above all his relationship with his listeners unique.''

Alastair Hetherington, an editor of Cooke's at The Guardian, said: ''His command of the English language was supreme, and his memory was so good that he needed no filing system.''