Speech radio has suffered a significant decline in listening figures, according to this quarter's Rajar results, with the World Cup and the hot weather cited as possible causes.
BBC Radio 4's Today programme's weekly reach fell from 6.32m to 6.12m year on year. Radio Five Live's breakfast show dropped from 2.32m to 2.25m and LBC 97.3's Nick Ferrari show slumped heavily from 4.87m to 3.51m.
LBC managing director David Lloyd told Press Gazette: "If you look at speech radio generally, it hasn't been a wonderful quarter for them. It is a bit puzzling, I have to say.
"If our audiences had gone towards World Cup coverage, I could have accepted it, but it just looks a bit odd. Even the mighty Radio 4's figures are down."
The total LBC network — including LBC 97.3 and sister station LBC News 1152 — showed an overall 8.8 per cent slump in reach quarter on quarter across all platforms.
LBC 97.3, which recently announced plans to broadcast to the regions on five DAB digital radio multiplexes, is down 29.1 per cent in London since the last quarter.
Lloyd said: "Rajar suggests that LBC's audiences have always been volatile. Things jump up and down quite a bit.
"I think the World Cup will have had some effect on our audiences, as would the very hot weather."
Overall, BBC radio reported a drop in its share quarter on quarter, falling to 54.7 per cent from last quarter's record of 55.4 per cent.
But the figure is still an improvement on the same time last year, when the BBC held a 54 per cent share of the radio market.
Radio Five Live is understood to have enjoyed a boost in listeners during the run-up to the World Cup, with a 6.3 per cent increase in reach year on year.
Five Live head of publicity Andy Bate told Press Gazette: "The feeling here is that it was a satisfactory quarter, although we're not yelling from the rooftops about the way that things have gone."
Bate said that it was "heartening" that some of the station's listeners were migrating towards Five Live's digital sister station, Five Live Sports Extra.
Bate added: "If you look at our performance in the context of medium wave generally, then we are doing very well to maintain the share and the reach that we do."
Commercial radio's weekly reach was down year on year from 31.19m to 30.74m, but had marginally increased since last quarter.
Six months after its launch, Edinburgh's Talk 107 recorded a 2 per cent reach and just 16,000 listeners.
In its application to Ofcom for the licence in 2004, the station — which is owned by UTV — had originally predicted a 12.5 per cent reach (140,000 listeners) within 12 months of broadcasting.
Talk 107 managing director Peter Gillespie said: "I am slightly disappointed, considering that it was our first Rajar.
"Launching a brand new speech service to an older, more sophisticated audience is a longer game than a relatively easily-formatted music station, and this is a long-term project for everyone involved."