The Conservatives have criticised reforms of media regulation which would allow the government to force BSkyB to carry BBC channels on its digital service.

A clause in the Communications Bill would enable Culture Secretary Tessa Jowell to insist that satellite broadcasters carry terrestrial public service channels.

They include ITV1, Channel 4, Five and the BBC's services.

She would be able to step in to negotiations and demand the channels were offered "fair and reasonable" rates to appear on BSkyB and other digital platforms.

Balance

But Tim Yeo, the Conservatives' trade and industry spokesman, said he was concerned that public service broadcasters might be given too much leverage.

"You'd think that if the balance should be tipped towards anyone it should be Sky rather than the BBC," he said.

The Department for Culture, Media and Sport said there would be an obligation for public service broadcasters to provide their services on digital satellite platforms.

"It's down to the two to negotiate on a price," said a department spokeswoman. "Ofcom, as the government's regulator, will review costs in terms of the price for them to provide their service."

The government wants public service broadcasts to appear on all three digital TV platforms - cable, terrestrial and satellite - once the analogue signal is switched off.