Jamie Theakston presents Heart 106.2 FM's breakfast show

Heart FM leapfrogged rivals Capital FM and Magic FM between January and March, the latest data has revealed, notching up a 7% share of total listening.

Shares in Capital Radio, which operates Capital FM, fell 1.6% on the news.

It is merging with GWR - owner of Classic FM - to form the UK's largest commercial radio group.

Successful change

Audience figures for commercial radio's flagship London stations are closely watched because they help to drive advertising revenues.

Heart's 7% listening share in the three months was up from 5.3% in the previous quarter, according to figures from industry body Radio Joint Audience Research (Rajar).

Our strategy will aim to take on the BBC and to champion the digital future Ralph Bernard, GCap Media Check Chrysalis share price

Previous market leader Capital slipped slightly, from 6.2% to 6.1% while Magic - which is owned by Emap - recorded a 6% share.

Phil Riley, chief executive of Chrysalis Radio, described the results as "excellent".

"They illustrate that the recent changes at our flagship London station have had a significant impact," he said.

National picture

Nationally, Chrysalis stations attracted 5.9 million weekly listeners, nearly 100,000 up on the previous period.

However, the group still remains well behind Capital Radio and GWR - owner of Classic FM - which attracted 7.8m and 10.1m weekly listeners respectively over the period.

The two companies will complete their merger next week. Ralph Bernard, chairman of GWR, said the merged company would have a clear position of leadership in the commercial radio sector.

"Our strategy will aim to leverage this position to take on the BBC and to champion the digital future," Mr Bernard - who will become chairman of the merged company GCap Media - said.

Chrysalis' shares closed up 9.5p at 156.75p while Capital Radio's shares fell 4.75p to 335p.

According to Rajar, total radio listenership increased over the period with the number of people tuning in to their radios - including BBC stations - rose 0.5% to 44.04 million.