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. It is quite a milestone. At the end of this month Radio 3 will mark its 50th anniversary: half a century of playing the best - and often most difficult - works of our classical music heritage. 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.