BBC Choice, one of the three existing digital television channels, will be relaunched as BBC Three, aimed at a younger market which the BBC has found increasingly difficult to capture.

The object is to create a suite of channels which live up to the BBC's ideals but also make sense in digital homes

Mark Thompson, BBC Director of Television

BBC Knowledge, the "learning" channel, is planned to become BBC Four. The corporation describes this as an "uncompromisingly intellectual" channel which will combine elements of BBC Radio Three, Radio Four and the current BBC Two.

The fifth channel will be the rolling news network BBC News 24. This will be complemented by the existing BBC Parliament channel which broadcasts the workings of Westminster.

The third and fourth channels will be given over during the day to two services aimed at children of different age groups.

The exact nature of the plans for these channels is unclear but the BBC says that it wants to create original British content, free of advertising and "an alternative to American content" that dominates the genre.

Plans trailed

Mr Dyke's plans for a multi-channel BBC were first mooted at the Banff Television festival in Canada in June this year.

A new BBC?

BBC One: Entertainment BBC Two: Factual BBC "Three": Youth BBC "Four": Arts BBC Five/Six: Children? BBC News 24: Existing

There, the BBC's director of television Mark Thompson said that public service TV had to change.

"Right now at the BBC, we're engaged in a fundamental review of our TV networks, the most far-reaching and challenging we've ever undertaken," he said.

"The object is to create a suite of channels which live up to the ideals which the BBC was created to promote, but which also make sense in modern digital homes."

He said that BBC radio had solved the problem in the 1960s by creating Radio 1, 2, 3, and 4.

With the launch of the news and sport BBC Radio 5Live in the 1990s, the BBC has met the needs of all licence fee payers, he said.

"If we can find the funds, and if we can convince the BBC's governors and the wider world that it's the right idea ... we should devote an entire digital channel to serious music and the arts, and to the world of ideas, in science, politics and philosophy."

'Bluechip channel'

And speaking in a BBC Online live chat forum in August, the controller of BBC One Peter Salmon set out the argument for a multi-channel BBC.

"We've got to prepare for the digital age," he said.

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"Pretty soon there'll be hundreds of channels and outlets available to our viewers.

"We have to prepare new strategies for all our channels to meet these new challenges.

"But BBC One will remain a bluechip, accessible, something for everyone, public service channel."

But commercial broadcasters say that the BBC has no business attempting to muscle in on the multi-channel age of digital television.

They say that the unique licence fee arrangements gives the corporation an unfair commercial advantage in a digital age.