RTE has announced a major shake-up of its radio schedules.
The move is seen as a bid to beat off growing competition and halt the drift of listeners to rival stations.
The radical changes involve some of the station's best known presenters: John Creedon, Myles Dungan and John Kelly.
Creedon, who only started in the 3.30pm slot in January, now has the graveyard shift from midnight to 2am.
The new Radio One line-up begins in September when presenter Derek Mooney will start a two-hour programme from 3pm, replacing Dungan's art show, Rattlebag, and Creedon's afternoon music programme.
"The success of Mooney Goes Wild has been noted," an RTE colleague said. The new show will be "something similar in presentation and tone - albeit without the animals". Changes to the Radio One schedule include an extra 15 minutes being tagged on to Joe Duffy's Liveline show.
Dave Fanning is set to join, resulting in a number of changes at sister station 2FM.
The new schedule comes four months after Ana Leddy was appointed head of the flagship station, and in the same week that rival station Newstalk was given a 10-year national licence.
After Mooney, there will be a three-hour drivetime show that is aimed at securing Radio One's place as the most popular drivetime station.
However, Leddy has resisted the temptation to start the drivetime show at 4.30pm, a time favoured by rivals Today FM and Newstalk, and liked by advertisers. The new show will start at 5pm with 90 minutes of news and current affairs - like its predecessor 5-7 Live - before Des Cahill takes over with 30 minutes of sport from 6.30pm. Dave Fanning then sees out the last hour of the show with music and movies.
With Rachael English having recently announced that she is to leave 5-7 Live, no decision has been made on who will present the first part of the show. There will be two hours of features, drama and arts programmes from 8pm with the popular John Kelly conspicuous by his absence.
"After seven years, Mystery Train presenter John Kelly has decided to concentrate on other broadcasting commitments," an RTE spokeswoman said.
A new arts programme will be on air from 11, but RTE could only say last night that it was "in discussions" with Myles Dungan to present it.
On 2FM current lunchtime host Damien Farrelly and night-time DJ Nikki Hayes are more or less swapping places, while Rick O'Shea has been moved to a late-night slot.