British lawmakers started work Friday on a draft law to regulate the nation's unruly newspapers as proposed by a major press inquiry, despite Prime Minister David Cameron's strong objection to the legislation.

Cameron's government is divided on the future of the press after the Liberal Democrats, the junior partners in his Conservative-led coalition, said they would join forces with the opposition Labour party and support a new law.

The rift was sparked by Thursday's publication of a report by judge Brian Leveson which, in the wake of the phone-hacking scandal at Rupert Murdoch's News of the World, proposed a new independent self-regulatory body backed by law.

Cameron warned immediately that he believes legislation could threaten press freedom -- while his deputy Nick Clegg, the Lib Dem leader, insisted it was essential to guarantee the independence of the new watchdog.

The prime minister said he accepted the vast majority of Leveson's proposals, which follow a year-long inquiry that heard from journalists, politicians and victims of press intrusion, but said a new law would put Britain on a slippery slope.

"I have some serious concerns and misgivings on this recommendation," he told parliament on Thursday.

"We will have crossed the Rubicon of writing elements of press regulation into the law of the land... We should think very, very carefully before crossing this line."

Actor Hugh Grant joined other victims of media intrusion in blasting Cameron for rejecting a state-backed watchdog despite his earlier pledge to do whatever Leveson proposed as long as it was not "bonkers".

"It wasn't and he didn't," Grant tweeted.

The British press currently regulates itself through the Press Complaints Commission, a body staffed by editors.

Its critics say it is toothless and partly responsible for Britain's failure to punish journalists for harassment, invasion of privacy and the hacking of voicemail messages.

Leveson proposed a beefed-up watchdog staffed by independent members, with the power to fine newspapers up to £1 million ($1.6 million, 1.23 million euros).

It is "essential" that the new body is backed up by legislation, the judge concluded in his 2,000-page report.

Lawmakers will go ahead with drafting a law, although culture minister Maria Miller suggested the Conservatives would use the process to attempt to persuade the Lib Dems and Labour that the new law would be unworkable.

Newspapers have broadly accepted the need for a tougher watchdog but were united Friday in their opposition to the regulation being enshrined in law.

"What is to stop MPs amending it now and in the future so that it no longer resembles the benign legislative vehicle envisaged by the judge?" asked the right-leaning Daily Telegraph.

Alan Rusbridger, editor of the left-leaning Guardian, accepted that the members of the new watchdog must not be "picked from amongst the old cosy club".

"There are lots of things that are much better about the Leveson regulator than the one that existed before or the one that the press proposed," he told BBC radio.

"It is right that is is open, that it is fair, that it's got sanctions, that it can investigate."

Some editorials said the onus was now on the newspapers to show they could come up with a tougher watchdog without legislation being required.

Cameron commissioned the Leveson Inquiry in July 2011 in the wake of revelations that the News of the World hacked the voicemails of a murdered schoolgirl and dozens of public figures.

Murdoch was forced to shut down the 168-year-old tabloid, and police have arrested dozens of people under three investigations spawned by the scandal.

Leveson, who heard from celebrities including actor Sienna Miller and Harry Potter author J.K. Rowling on their treatment by the media, said the press had for decades "wreaked havoc with the lives of innocent people".