Correction: Earlier versions of this story misidentified the chairman of the Press Complaints Commission’s funding arm. He is Guy Black, not Conrad Black.

After nine months of hearings sparked by phone hacking at Rupert Murdoch’s News of the World tabloid, a landmark report released Thursday recommended new, independent oversight of newspapers in what was seen as a day of reckoning for the British press.

The nearly 2,000-page report sets up a politically explosive battle over how to eradicate a “subculture” of illicit news gathering in dark corners of old Fleet Street without treading on freedom of the press. It calls for a new press law — the first since the 17th century — that would safeguard media freedoms in Britain while also creating an independent body to act as a watchdog on an industry that has, thus far, largely regulated itself.

The release of the report, “An Inquiry Into the Culture, Practices and Ethics of the Press,” immediately divided the British political establishment, with Prime Minister David Cameron saying he has “serious concerns and misgivings” about a media watchdog underpinned by law.

“For the first time we would have crossed the Rubicon of writing elements of press regulation into the law of the land,” Cameron said on the floor of Parliament. “We should, I believe, be wary of any legislation that has the potential to infringe free speech and a free press.”

Britain’s famously aggressive print media — and particularly its salacious tabloids — came under fire last year following revelations of widespread phone hacking at News of the World, targeting celebrities and crime victims, including a 13-year-old girl who was murdered. While singling out the now-defunct paper for particular wrongdoing, the report, issued by a panel headed by Lord Justice Brian Leveson, amounted to a far broader indictment of criminal behavior and ethical lapses in the press.

News media and free-speech groups in Britain have bitterly opposed any legislation smacking of government regulation of the press. The report appeared to sidestep their biggest fear — some form of government oversight. But skeptics remained cautious about the part of the Leveson proposal that would undergird the independent oversight body through a new press law.

In presenting his report Thursday, Leveson said part of the proposed law would be designed to protect press freedoms, serving almost like the U.S. Constitution’s First Amendment. He insisted that he was not suggesting government oversight, and he lauded the domestic press as a pillar of British democracy and a treasured haven for the “irreverent, unruly and opinionated.”

But he said it was clear that the current Press Complaints Commission, peppered with newspaper editors and limited in its powers, was not working. Instead, he called for an independent body — free of influence from both the government and news media groups — to be enshrined in law. The powerful new body could investigate and arbitrate claims made by victims of media wrongdoing and issue fines of as much as $1.6 million.

The panel’s nonbinding recommendations put immediate pressure on Cameron. Although he expressed caution about establishing an independent oversight body based on law, he is facing demands from the opposition Labor Party and his own coalition partners, the Liberal Democrats, to fully adopt Leveson’s proposal.

“The ball moves back into the politicians’ court,” Leveson said at a news conference Thursday. “They must now decide who guards the guardians.”

The Press Complaints Commission that now regulates the press here is made up of editors and other notable figures and was criticized last year in the wake of the phone-hacking scandal as a “toothless” organization.

David Hunt, the commission’s chairman, has put forward his own plan for a rehabilitated independent commission with a new “compliance” arm that would be able to impose fines and enforce standards, powers the current body lacks. Guy Black, chairman of the current commission’s funding arm, has also recommended retaining a system of self-regulation but expanding the commission’s authority so it could launch investigations and levy larger fines.

But Leveson dismissed those options for beefed-up self-regulation as not going far enough. “A free press in a democracy holds power to account but, with a few honorable exceptions, the U.K. press has not performed that vital role in the case of its own power,” he said.

Many of the practices documented by the Leveson report are already illegal under British law, suggesting that the problem is as much one of tolerance or inept law enforcement as of journalistic ethics. The report, however, found no evidence of widespread wrongdoing by law enforcement officials, although it cited specific examples of gray areas, including cozy relationships that led to unofficial tip-offs and informal briefings.