"It is a worrying report for 2FM. Their breakfast show is down 15% on average quarterhours; the Will Leahy Show is down by 24%, which is why RTE is focusing so strongly on overall programme reach, " said Conor Hanover, broadcast director with media buyer Mediaworks.

The average quarter-hour measure is the main system used by advertisers to determine their radio budget allocations because it gives them an accurate measure of how many listeners are listening to a station in each quarterhour block during the day.

"It measures what you are paying for. It doesn't look at how many people are listening to a show as a whole but at one spot in time, " said Hanover.

He said that the extent of 2FM's difficulties could be gauged from the fact that it is has only 5,000 more listeners per average quarter-hour between 7am and 7pm than Today FM.

"In 2001, there was a 78,000 difference but while TodayFM has been growing listeners, 2FM has been shedding them."

Hanover said, however, that it was too early to conclude that this year's revamp of the station had failed, particularly as the new figures cover the 12 months from last July.

A spokeswoman for RTE said the station was satisfied with its listenership figures, though even using its preferred overall audience figures, 2FM's much-hyped Colm & Jim Jim Breakfast Show, which launched in March, has lost 6,000 breakfast listeners.

"2FM is really targeting 15to 24-year-olds and this segment has been increasing in the breakfast slot and our breakfast audience has also increased by 2% in Dublin, " the spokeswoman said.

She also said the station was encouraged by Radio 1's figures, which showed that its weekday market share had increased by 0.4%, indicating that last year's controversial revamp of the station's schedule was working.

By far the biggest beneficiary in the JNLR survey, however, was south-east regional youth station Beat 102-103, which is the process of being bought by Thomas Crosbie Holdings (TCH). It increased its weekday reach figure to 18%, overtaking Today FM and 2FM in the process.

The station's managing director, Gabrielle Cummins, said that part of the reason for the station's success was the weakness of 2FM in its 15 to 24-year-old target market.

"The perception would be that they are the national youth alternative but they haven't been delivering, " she said. "We've always said that we would complement the local stations and we are but we are hitting the nationals."