This event will be celebrated with live broadcasts from the five BBC orchestras, invitation concerts devised by previous controllers, archive features and a specially commissioned history of the station, launched in 1946 as the Third Programme.
In parallel, however, there will also be a more difficult anniversary that Radio 3 will ponder in private: the 50-year debate over whether it should exist at all. For just as it has been lauded for half a century for its high-quality classical music, so it has been as constantly vilified for its elitism, unpopularity, self-indulgence and - given that its pounds 56m bill is paid by the licence-payer - appalling expense.
These questions, which have swirled around the network since its launch, are more relevant today than they ever were. The Third Programme began transmitting into a classical broadcasting void (or near void), but since then broadcasting has been utterly transformed. Television gives substantial space to arts and music; commercial radio has expanded exponentially; and Classic FM has famously won five million listeners since it launched in July 1992.
Radio 3, on the other hand, can claim a little under 2.3 million listeners, down 100,000 since spring, and down 200,000 since Nicholas Kenyon, its controller, took the helm in early 1992. Unlike Classic FM, it generates no advertising income - devotees can only pray that this state of affairs continues - and has apparently existed in an idealistic time-warp.
Mr Kenyon's attempts to rectify the situation have only intensified the debate. Changes he has introduced include hiring Paul Gambaccini, a former Radio 1 DJ, to present the morning show, encouraging presenters to talk more, and moving Composer of the Week to noon. Even more controversially, the network ran an advertising campaign showing tattooed lorry drivers conducting imaginary orchestras over the slogan "Ludwig Van".
Mr Kenyon, for his pains, has earned the unkind nickname of "the Axeman" and a reputation in some circles (Gerald Kaufman, the MP; Bamber Gascoigne, the presenter) as a Gerald Ratner of the airwaves. The reality is different, however. While Mr Kenyon appreciates the need to "warm up" Radio 3 and ease new listeners in, he believes that Radio 3 should stay in the top slot, intellectually and musically.
And so it should. Far from running screaming at the "threat" of Classic FM, it should stick to its guns. Let Classic FM play the pretty pieces that are so assiduously plundered for adverts. Let it play only the accessible parts of a symphony or offer classics by numbers. Radio 3 should remember what it is so stubbornly loved for: spare, high-quality presentation, live concert broadcasts, attention to contemporary composers, new drama, jazz, playing whole symphonies, and brushing the dust off neglected works.
This is what the licence fee helps pay for, and a lot more. Radio 3 helps to support three of the BBC orchestras (the Scottish Symphony, BBC Philharmonic and BBC Symphony) so indirectly providing cheaper ticket prices for their concerts. It encourages contemporary music and drama by commissioning new works and has introduced classical music to literally millions, via the Proms.
Detractors argue that that is all very laudable, but not at their expense, and they are right, if they do not want to be supported by the state when they lose their job, or get sick, or cannot afford to fight a court case. For whether you are talking about tax or a television licence fee, it is exactly the same principle. That kind of quid pro quo - where we all contribute to the cost of services that we don't necessarily all use - is exactly what civilised society is about. For if Radio 3 stops serving the most informed and "able" classical music listeners, who will?
The reality is that the fundamental question to be addressed today is not whether Radio 3 should exist, or be given so much money to do so, but how to ensure that it continues to broadcast the same way for another 50 years. This is no imaginary danger. There can be no doubt that, just as it has occurred to the Government that Radio 1 would make a lot of money if privatised, it has cast avaricious eyes over Radio 3.
Who knows whether the highest echelons of the BBC would - privately of course - accept such a loss if they won the continuation of the licence fee in return (another quid pro quo, although a considerably less palatable one). Such a scenario would, after all, explain its apparently irrational decision in Radio 1's case to drive its listenership down in terms of age, alienating millions of listeners.
It would be so easy to hive off the former Third Programme, invite the advertisers to flood in, and watch the pound signs spin. Then, as in the newspaper market, the slide would be down to the middle. Radio 3 would be forced to adopt Classic FM tactics in earnest and the likes of Paul Gambaccini, instead of being booed off-stage, would be here to stay.
Gerald Kaufman complained volubly when Mr Kenyon set about making Radio 3 more accessible that he was going to eat it for breakfast rather than listen to it. But there are millions who would still like to tune in to it in the mornings. Mr Kaufman, and influential critics like him, should be directing their energies at making sure that Radio 3 does not end up as shreddies in this Government's mania for dismantling.Reuse content