It promises to be a long autumn of encomiums to Gay Byrne, whose announcement that he's leaving radio on Christmas Eve marks the beginning of the end of an era - if you know what I mean.

This column hereby makes a solemn commitment not to get carried away. In spite of what Dr Johnson and Eamon Dunphy have to say about consistency, I reckon I've griped about Gaybo slightly too often (and, of late, listened to him slightly too rarely) to make a plausible transition to singer-of-praise.

I could drag out the readymade, cliched and perhaps backhanded compliments, but my fingers seize up at any attempt to type consummate professio - however apt the label may be in this case. For this listener, Gay Byrne has as often been irritating as entertaining - his populist conservatism, often verging on ignorance and sometimes crossing the verge, not my cup of tea at all. When the Gay Byrne Show had a more important and eclectic role than it does nowadays, he could be caught out of his depth on many issues.

And yet . . . no Irish broadcaster is a better interviewer and none has been more in touch with his audience. His reduction of broadcasting hours in recent years was as much a mark of his total commitment to being engaged with his listeners as of fatigue - he would not dream of being a tired or distracted Uncle Gaybo, a half-hearted version of himself.

In contrast to Pat Kenny, with interviewees Byrne has rarely seemed anxious to jump in with his own knowledge or his own views. His interviews have a relaxed, discursive, unpredictable nature that has often been compelling.

In the last couple of years, he gracefully acknowledged that his days as the Voice of Ireland (anyone's days as the Voice of Ireland) were over by moving his programme to a later, more leisurely time-slot.

The latest incarnation of the Gay Byrne Show - which never really became the musicled programme he talked about - has been surprisingly, admirably devoted to older listeners. It's as if Gaybo and his team recognised the new pluralism of the country, and of the radio market, and selected as listeners the people who've been with him all along. One of the many questions now faced by Radio 1 programmers is what to do with that unfashionable, increasingly neglected audience. Grannies don't figure prominently in the strategies of most major advertisers, who would be as happy to see them abandoned to the vicissitudes of local radio; fortunately, some stations outside Dublin continue to serve them.

Byrne's retirement is widely viewed as giving Helen Shaw a chance to break up the station's star-dominated schedule - which means, presumably, no transfer for Gerry Ryan, whose role at 2FM is more important than ever after the departure of Ian Dempsey.

However, the real business end of Radio 1's morning schedule still looks entrenched, and it's hard to see how radical change can be introduced without alienating, in particular, Pat Kenny.

There's little doubt that the competition is beginning to warm up. Today FM with Dempsey suddenly has a morning profile to build upon, and at the other end of the daytime schedule it's got the momentum. While Today FM has apologised for some of its own "internal tracking" slipping recently into the public domain, you don't need a marketing firm to tell you that The Last Word (Monday to Friday) is a growing boy; you just need to listen. Wherever a man or men are in the company of a radio - be it in a pub, a garage, a shop, a delivery van - you are extraordinarily likely to hear that programme in the early evening.

Eamon Dunphy's unlikeliest replacement, Fergus Finlay, has done a terrific job in Dunphy's absence. Last week, Finlay phoned the man himself at his holiday retreat to discuss Michelle de Bruin's suspension; liberated from the silence of the interviewer, Dunphy delivered a long but pointed thesis about the media's prior self-censorship on the issue. If the papers and RTE could devote a virtual conspiracy of silence to "hoodwinking" the Irish public on this relatively trivial matter, Dunphy asked, what else are we not hearing about?

Right on, Eamon - the new Gay Byrne.