Rupert Murdoch is reportedly interested in Channel 5

A new Office of Communications (Ofcom) will be the single regulator for British broadcasting, replacing the five current separate watchdogs for TV, radio and telecommunications.

Ofcom will be fully operational by the end of this year.

The UK's Culture Secretary, Tessa Jowell, said it was only the start of a long process.

"Ofcom must now deliver a new regulatory system that will be a light touch and unobtrusive wherever possible, but decisive and robust wherever necessary," she said.

The act will also reform the rules on media ownership, introducing deregulation to promote competition and investment in the broadcasting industry.

Fears

This part of the bill caused it to be delayed after an opposition challenge in the Lords to stop media magnates such as Rupert Murdoch being able to buy broadcasters such as Five, formerly Channel 5.

But the proposed amendment was defeated by 167 votes to 137 in the House of Lords last week.

A concession was made to the protesters with the inclusion of a "plurality test", after talks with film producer Labour peer Lord Puttnam.

The tests will ensure media owners are committed to a balanced and impartial presentation of news and comment.

Lord Mackintosh, for the government, said this would allow the secretary of state to intervene in cases where she believed a merger caused sufficient plurality for it to be blocked or for conditions to be attached.

Concern has been expressed that broadcasting deregulation under the act could see US-style "dumbing down" of British TV.

Other key elements of the act include access to a choice of high quality services and ensuring that public service principles remain at the heart of British broadcasting.

The changes mean the biggest shake-up of the British media in more than a decade.

"I believe that in its final version, the act will deliver on its central aim - to bring the interests of us all as citizens and consumers to the fore, while increasing investment and maintaining high standards, " said Ms Jowell.