Embarrassed by Miss Marple, and now Chris Tarrant. What went wrong, Johnny Vaughan?

He once had the golden touch, the quick-witted host with a winning personality but Johnny Vaughan now seems more likely to turn programmes to stone. New figures reveal that his breakfast radio show has lost a quarter of a million listeners.

After masterminding a series of disappointing projects that never fulfilled his early promise, Vaughan's career looked like it was about to enjoy a renaissance this year. He took over from the veteran radio DJ Chris Tarrant as the host of Capital 95.8FM's flagship London breakfast show in April.

His television career was given new life, with a prime-time Saturday night show on BBC1, Passport to Paradise, which reunited him with Denise Van Outen, his former sidekick on Big Breakfast.

But, just a few months on, the high hopes that both Capital and the BBC shared for Vaughan look close to being dashed.

Capital's breakfast show only pulled in 1.19 million listeners in the three months to June, a drop of 254,000 from the same period in 2003, according to the radio industry body Rajar. Compared to Tarrant's last three months, weekly listeners fell by 187,000. The disappointing figure comes afterPassport to Paradise recorded a miserable 2.8 million viewers last Saturday, humiliatingly beaten in the ratings by a repeat of Miss Marple.

Capital Radio put a brave face on the figures yesterday, insisting it was "very early days" for Johnny and pointing out that he was only on air for nine out of the 13 weeks covered by the survey.

Capital's managing director Keith Pringle said: "Inevitably, if you go down it is slightly disappointing but radio is a long-term game. It takes a long time to launch a breakfast show, but Johnny has hit the ground running. I have an extremely good feeling about the show. To be number one in London is no small feat and we're proud of what he's done."

The figures tell a more alarming story. While Capital is still the number one commercial radio breakfast show in London, Vaughan's rivals are fast catching up.

Heart 106.2FM's breakfast duo Jono Coleman and Harriet Scott put on 138,000 listeners to 971,000, Classic FM is up more than 36 per cent year on year to 859,000 and Virgin's breakfast show has won another 40,000 listeners in London.

Nationally, Radio 2's Terry Wogan remains the nation's favourite breakfast show host with 8 million listeners.

City analysts are concerned about Vaughan's performance. Simon Bumfrey, a director in Barclays media team, said the drop in Capital Radio's audience, which fell overall by 517,000 to 2,107,000, was larger than expected. "It was generally accepted that there would be uncertainty following Chris Tarrant's departure from Capital and Johnny Vaughan's arrival. It shows the importance of a strong breakfast show to help build a large listening base throughout the day," Mr Bumfrey said.

Vaughan's arrival at Capital was supported by a massive promotional campaign starring the London-born father of two who performed a song and dance routine at various landmarks around the capital.

The station hoped Vaughan could recapture the appeal he enjoyed during the heyday of Channel 4's Big Breakfast, which he joined in 1997. His spontaneous wit was ideally suited to the programme's wacky style, with highlights including his irreverent reviews of that day's newspapers. Together with Van Outen he was considered part of a dream team, living up to the standard set by the show's original presenter, Chris Evans.

When he left Big Breakfast three years later the show's viewing figures went into a decline from which they never recovered. Vaughan looked set to become one of television's most popular presenters. It was a significant turnaround for the former public schoolboy, who had served a 25-month prison sentence for dealing cocaine.

The BBC was impressed with his potential. In 2001, he signed a £3m "golden handcuffs" deal with the corporation with hopes for a range of popular entertainment series.

However, his debut BBC1 chat show Johnny Vaughan Tonight attracted just two million viewers and was relegated to the digital channels BBC Choice and BBC3, before being axed altogether.

'Orrible, a sitcom that he wrote and starred in for BBC2, was critically panned. It looked as though his career had drawn to a premature halt, until autumn 2003 when he was signed up to present a Radio Five Live show Fighting Talk, and then named as Tarrant's successor.

Doubters have questioned whether Vaughan has what it takes for radio after a career spent exclusively in television, but Mediaweek editor Tim Burrowes thinks Vaughan can still "turn it round" on Capital.

Shortly before joining the breakfast show, Vaughan told The Independent that his grandfather had always driven Rolls-Royces but never enjoyed them because he was always listening for the rattle. His mother, Fay, a psychotherapist, told her son "enjoy the Roller, don't listen for the rattle".

Vaughan said: "I don't feel any pressure when I go in to face the microphone. I have no sense of audience out there." Wits imitating his own repartee might begin to joke that unless he reverses the downward trend, there may be no audience.