Veteran Radio 4 broadcaster Alistair Cooke is retiring after 58 years at the helm of his show Letter From America.
Alistair Cooke has spent over 50 years reporting on American affairs
The 95-year-old joined the BBC in 1934 as a film critic before starting up US current affairs and historical programme Letter From America in 1946.
The show is the world's longest-running speech radio programme.
Cooke, who was absent from the show last week due to illness, will not record any new shows but Radio 4 will air archive shows for several weeks.
The BBC said Cooke had decided to sign off following advice from doctors
Cooke said: "I can no longer continue my Letter From America.
"Throughout 58 years I have had much enjoyment in doing these talks and hope
that some of it has passed over to the listeners, to all of whom I now say thank
you for your loyalty and goodbye."
Since Letter From America began, Cooke has presented 2,869 shows, making up more than 717 hours of broadcasting time. This does not include other radio shows he has fronted.
The popular programme is listened to by people around the world via the BBC's World Service across Europe, Asia, New Zealand, Africa, the Americas and the Middle East. It is also available online.
Cooke has also taken part in a wide range of television programmes but is perhaps best known for the BBC's Alistair Cooke's America, which was aired around the world.
His ground-breaking cultural television show Omnibus changed the face of American television in the 1950s.
Tapes of the programme were placed in every public library in the US and a stream of successful books culminating in the title America, which sold two million copies.
Mark Byford, acting BBC director general and former World Service
director, thanked Cooke for his "unparalleled contribution".
He said: "Alistair Cooke has been one of the greatest broadcasters ever, full
of insight and wisdom.
"He has brought enormous pleasure to millions of listeners, both in the
United Kingdom and around the world."
Jenny Abramsky, director of BBC radio and music, said Cooke's letters were a
"unique legacy" which had "stimulated and entertained millions".
"I can still remember listening at university to his letter when Robert
Kennedy was shot.
"His description of the small pantry passageway in San Francisco brought home
the horror of Kennedy's death in a personal human way that marked all his
"We are very sorry he has decided to retire but are grateful for all the
years he has devoted to the BBC."
In 1973, Cooke was awarded an honorary knighthood and in 1974 he addressed the United States Congress on its 200th anniversary.
He also received an award from Bafta for his contribution to Anglo American relations and a Sony Radio Award for his services to broadcasting.
Cooke was born in Salford, England in 1908. He now lives with his second wife Jane White in New York.