Chrysalis, the media company, has predicted that its Heart radio station in London will overtake Capital Radio's flagship over the next year.
Although Heart briefly passed 95.8 FM's market share in London for one quarter last year, the last two listening surveys have seen it slip back.
Richard Huntingford, the Chrysalis chief executive, said Heart would get back in front - permanently. He said Capital's loss of its star DJ, Chris Tarrant, who hosted the key morning show, meant its leadership of the London breakfast slot was up for grabs.
He said half of Mr Tarrant's listeners were over 35 - an audience that was "naturally" much more at home with Heart's style and music than with Capital's youth-orientated programming.
"When we got past Capital [last year] we said it was 18 months too early. We didn't think it would happen until after Tarrant left. We think the new Capital breakfast show provides a major opportunity. Our goal is to make Heart the number one station in London and we think it is very achievable."
Chrysalis, which also has a books and music division, reported a 19 per cent rise in underlying pre-tax profit to £3m for the half year to 29 February. Radio revenues were up 23 per cent and the company said a similar rise in radio sales had been maintained in March and April.
Losses at the troubled book division more than halved to £700,000. The company said it was looking to get this business back into profit before making a decision on its future. Analysts expect the books interests eventually to be sold.
Chrysalis said it had launched a new division to exploit the growing market for mobile phone ringtones, which are becoming much more sophisticated "real" tones, and the upcoming development of full song downloads.