The expansion of digital radio has boosted the number of listeners to a record level but a radical change to popular programmes is sending Radio 4 listeners over the edge, new figures have shown.

Almost 200,000 listeners left The Archers as scandalous storylines reached a peak, says Rajar, the audience research bureau. And the arrival of Kirsty Young as the replacement for Sue Lawley as presenter of Desert Island Discs last October prompted 100,000 Radio 4 listeners to switch over.

The BBC shrugged off the slump as mere fluctuations in the popularity of programmes.

Audience figures for The Archers dipped when Ruth Archer risked her previously happy marriage by conducting a clandestine affair. Ambridge’s first gay wedding followed weeks later.

Rajar figures showed a weekly audience of 4.44 million, down 169,000 on the previous quarter, and 197,000 year on year. The BBC was quick to deny suggestions that The Archers had “jumped the shark” – the moment when a programme strays so far from its established path that it struggles to retain credibility with its audience. Examples of the phenomenon include the 1993 air crash that wiped out the cast of Emmerdale, and the marriage of Daphne and Niles, which preceeded the end of Frasier.

Mark Damazer, the controller of Radio 4, said: “We expect these small fluctuations in listening figures over the course of a year and this quarter’s figures are well within the usual range.”

Mr Damazer said that he was “delighted with the continuing success of The Archers” and pointed out that the Rajar figures did not include the one million listeners catching up with episodes online.

The first figures for Desert Island Discs since Young, the head newsreader on Five News, replaced Lawley revealed that the programme had lost 130,000 listeners.

Young’s audience was 2.54 million, compared with 2.67 million for the previous three months when Lawley was at the helm and down from 2.69 million for the same period of 2005.

However, Lawley’s ratings dipped below 2.5 million on occasion and critics say that Young has not been given a sufficient number of headline-making castaways. Commercial radio stations complained yesterday that the BBC had spent millions of pounds on an advertising campaign for Radio 2 in which Elvis Presley appeared to be on stage with an improbable ensemble of rock and pop stars including Noel Gallagher and Keith Moon.

The advert helped Radio 2 to pile on 530,000 listeners over the past quarter, taking its total audience back over 13 million. Terry Wogan, on Radio 2, remained the most popular breakfast DJ with 8 million listeners, while Chris Moyles reached an audience high of 6.82 million on Radio 1. The Today programme audience is down 0.3 per cent over the year, with 6.2 million listeners.

More than 45 million people tune in to the radio each week – the highest figure since Rajar began keeping track of the nation’s listening habits in 1992. The rise was attributed to growing numbers of people tuning in via the internet, digital television or their mobile phones.

Digital receivers, which are are now found in 16 per cent of British homes, are challenging the established radio stations with digital-only services such as Planet Rock and the archive comedy channel BBC7.

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