Commercial radio listeners will still hear plenty of Anastacia

With 55 local analogue radio stations, 93 digital stations and a national frequency, the new group will broadcast to 18 million people.

Both Capital and GWR insisted their stations would retain their local identity after the merger. But one industry critic warned that in the long-term, bland US-style syndication was a threat.

The merger brings together well-known stations like Classic FM, Capital, Capital Gold and Xfm, as well as a plethora of local broadcasters.

At present Capital has separate playlists for alternative station Xfm, youth station Choice, classics frequency Capital Gold and London station Capital.

Its FM network of local stations operate from a centralised playlist, with variations so local bands and differing regional tastes can be accommodated.

Consolidation worry

Capital spokeswoman, Elly Smith, said this situation would remain unchanged and that music programming would continue to be mainly local, rather than networked.

"Programming is remaining unaffected. We don't have too many shared programmes."

But Dave Ferguson, chairman of the British Academy of Composers and Songwriters, told BBC News Online the long-term prospects could be blander networked shows with no room for local talent, as the group tried to cut costs.

"We don't welcome this. All the evidence that we see shows that merging of companies like this and consolidation generally in the radio sector leads to a decrease in diversity.

"The way they save money is by centralising playlists and centralising programming."

Capital FM network top five Anastacia - Sick and Tired Keane - Bedshaped Maroon 5 - She Will Be Loved Scissor Sisters - Mary Sugababes - Caught in a Moment

Mr Ferguson said the example of the US, with giant groups such as Clear Channel, showed consolidation led eventually to the widespread used of networked programmes instead of distinct local content.

"It is so vital that the BBC charter is renewed. It becomes the sole saviour of local diversity in a consolidated sector."

GWR also dismissed any notion that the local identity of stations would be lost.

Capital and GWR believe the merger will help them play a key role in the developing digital market, putting them in a better position to dominate the commercial market, and in the short term getting major benefits in the sale of advertising.

Together, Capital and GWR will have 40% of the UK's commercial radio advertising revenue - a market which is estimated at �660m annually - and reach 36% of the UK commercial radio audience.