The great and the good frequently appeared on what became known as the JY Prog.

Politicians, including prime ministers, have regularly beat a path to Sir Jimmy Young's door.

Margaret Thatcher, famously, joined him at the microphone 14 times.

Sir Jimmy Young in 1952

Tony Blair's press chief, Alistair Campbell, said in 2001: "Whichever BBC source suggested Jimmy Young is a soft interviewer clearly knows nothing about interviewing, and even less about Jimmy Young."

John Major reportedly refused to appear on the programme again after Sir Jimmy told him: "The voters took Lady Thatcher seriously while they laugh at and make fun of you."

While BBC Radio 2 has undergone many changes, 81-year-old Sir Jimmy has endured.

He has ruled the airwaves on the radio station since 1973, his show acquiring almost listed status.

Early pop star

Before his broadcasting career began he was one of the UK's earliest popular music stars.

Jimmy Young: A national institution

He first entered showbusiness in 1949, when radio listeners heard him performing songs at the piano.

After the creation of the charts in 1952, he had five top 10 hits, including two number ones in 1955 - Unchained Melody and The Man from Laramie, becoming the first UK artist to reach number one with two successive singles.

But his star waned as rock and roll won the hearts of music lovers, and he moved to radio.

His first jobs were as the host of Housewives Choice on the BBC's Light Programme - the forerunner of BBC Radio 2 - and also working for Radio Luxembourg.

Born in Cinderford, Gloucestershire, Sir Jimmy's first job was as a baker's assistant before he joined the Royal Air Force, spending seven years as a physical training instructor based in India.

Later, he became a clerk at the Ministry of Education, and managed a hairdressing salon.

BBC Radio 1 launch

Politicians have been quick to appear on the show

He was among the first DJs to work on BBC Radio 1 when it launched in 1967, transferring to the more sedate Radio 2 in 1973 for the JY Programme - a mixture of current affairs, chat and music.

The first interview on the new programme was with Erin Pizzey from Chiswick Women's Aid, a refuge for battered wives.

As well as interviewing every British prime minister since 1964, he interviewed other big names of their day, such as Neil Kinnock, David Owen, David Steel and Michael Foot.

Royal guests included the Princess Royal, Prince Philip and Princess Grace Of Monaco.

His show travelled the world too, coming live from the former Soviet Union, Israel, Japan, Hong Kong, 1970s Rhodesia, and Egypt where he interviewed then-president Anwar Sadat.

But in the late 1990s, while Sir Jimmy remained a figure of continuity, Radio 2 was changing around him, as many of the station's shows were changed to attract a younger audience.

In particular, the then 79-year-old presenter found himself handing over to Steve Wright's afternoon show each day - just a few years earlier Wright had been hosting largely the same show on the brasher Radio 1.

Tough act to follow: Jeremy Vine replaces Sir Jimmy in January

While discreet discussions took place about a possible replacement for Sir Jimmy, the BBC was embarrassed in 2001 when Radio Five Live's Nicky Campbell said he had been approached to take over Radio 2's lunchtime slot.

'Pursuit of youth'

Sir Jimmy - who was knighted that year - was furious and suggested success had made people "desperate" to get his job.

"Unless of course, in the ageist pursuit of youth, someone decides to ignore my record-breaking ratings and fire me," he added.

MPs joined listeners in lobbying the BBC to save the programme.

But early in 2002, it was announced his lunchtime show was ending, and he was going to move to a new weekend slot.

However, later in the year, after recovering from a hip operation, he decided to take a complete break from broadcasting, adding: "I appreciate how hard the BBC tried to keep me but I have decided not to accept their invitation."

Some of his listeners are sceptical though. One message posted on his show's website reads: "If the BBC don't want you Sir Jim, I suggest you go to another broadcasting company and name your own salary - you'll get it, be sure of that, and your listeners will follow you in droves."

Whatever the facts behind Jimmy Young's departure, his replacement, Jeremy Vine, will have a lot to live up to when he opens his microphone for the first time in the new year.