The British press is anxiously awaiting today’s results from a major inquiry into their ethics and standards, but the report will also represent a dilemma for Prime Minister David Cameron.

Cameron is underno obligation to implement Leveson’s recommendations but, having taken the decision to set up the inquiry, he is likely to face heavy criticism if he takes no action

Cameron set up the judge-led Leveson Inquiry last year in response to revelations that Rupert Murdoch’s News of the World tabloid had hacked the phone messages of Milly Dowler, a murdered schoolgirl, as well as targeting dozens of crime victims, celebrities and politicians.

Over eight months of hearings overseen by one of Britain’s most senior judges, Brian Leveson, the inquiry has looked in detail at the methods of the British tabloids, who used to pride themselves on their aggressive tactics.

A total of 474 witnesses gave evidence, with hacking victims including actors Hugh Grant and Sienna Miller among the first to testify.

Leveson’s recommendations could usher in a radical change to the way media organisations operate in Britain.

The British press is currently self-regulated, overseen by the Press Complaints Commission, which is staffed by editors.

Cameron is under no obligation to implement Leveson’s recommendations but, having taken the decision to set up the inquiry, he is likely to face heavy criticism if he takes no action He also faces deep divisions in his own party and even a possible rebellion within the Conservative ranks if he agrees to any statutory regulation of newspapers.

Forty-two MPs from the centre-right Conservatives – who are the senior partners in a coalition Government with the centrist Liberal Democrats – wrote a letter calling for strong new press laws.

The leader of the main opposition Labour party, Ed Miliband, has warned Cameron that Leveson’s proposals must be swiftly implemented by Parliament as long as they are “reasonable and proportionate”.

Miliband said that if the Government rejects the Leveson report, victims of phone hacking and harassment by the press would view it as a “breach of the promise” made to them by politicians in the wake of the hacking scandal.

At the same time, newspaper editors have warned that state regulation of the press would limit press freedom and hamper investigative reporting. The editor of another newspaper owned by Murdoch, The Times, conceded that the press had “forfeited” the right to continue policing themselves.

Editor James Harding said he backed tougher regulation of newspapers but cautioned that the state must be kept out of it.

“I believe we need to move to a system of independent regulation with a judicial, but not a statutory, backstop,” Harding wrote in a comment piece. It would involve “an independent, muscular regulator” which could give wronged parties rapid redress, he said, but “this is to be run by the public, not editors of proprietors”.

Cameron’s office has rejected suggestions that the Prime Minister has already decided to resist the introduction of statutory regulation, saying he was “open-minded” until he sees the report.

The inquiry has been an uncomfortable process for Cameron, whose close links to Rebekah Brooks, the former chief executive of Murdoch’s British newspaper arm News International, came under the microscope when gave evidence. The British PM suffered the indignation of having his private text messages to Brooks – signed off with “lol”, which he mistakenly thought meant “lots of love” rather than “laugh out loud” – revealed to the public.

Whatever Leveson recommends, the phone-hacking scandal has already left deep scars on the British press. Murdoch shut down the News of the World – a Sunday tabloid which was then Britain’s highest-selling newspaper – last year as public anger at the hacking allegations grew.

The scandal has spawned three criminal investigations – one into alleged bribery of public officials, another into phone hacking itself and a third into computer hacking.

Brooks and Andy Coulson, a former News of the World editor who became Cameron’s communications chief, have both been charged with phone hacking and bribery.

Key questions about the inquiry

Who is Leveson?

Brian Leveson (right), or Lord Justice Leveson as he is formally known, is one of Britain’s most senior judges.

The 63-year-old was appointed by Prime Minister David Cameron in July 2011 as chairman of an inquiry into the ethics of the press following the phone-hacking scandal at Rupert Murdoch’s News of the World tabloid.

The bespectacled judge was the lead prosecutor in the 1995 trial of serial killer Rosemary West, who was convicted of murdering 10 women with her husband Fred West in their ‘House of Horrors’ in Gloucester, western England, and is currently head of the Sentencing Council for England and Wales.

As head of the inquiry he is assisted by a panel of six people: a human rights activist, a retired police chief, a ormer telecoms regulator, two journalists and the former chairman of the Financial Times.

One of the most public faces of the inquiry has been the Counsel to the Inquiry Robert Jay, the bearded lawyer who has had a series of sparring matches with key witnesses.

What are the tasks of the Leveson inquiry?

The Leveson inquiry is divided into two parts.

The first part, which is due to report today, is examining the culture, practices and ethics of the media. It will focus in particular on the relationship of the press with the public, police and politicians.

The report will make recommendations on the future of press regulation “consistent with maintaining freedom of the press and ensuring the highest ethical and professional standards,” according to its website.

The second part of the inquiry is into unlawful conduct within News International, the British newspaper wing of Murdoch’s US-based News Corp. empire, but will not take place until after separate criminal proceedings have concluded.

Who has testified to the inquiry?

The Leveson inquiry has heard from 474 witnesses since November 2011.

The first group to testify were hacking victims, ranging from celebrities including actor Hugh Grant, singer Charlotte Church and Harry Potter author J.K. Rowling, to the parents of murdered schoolgirl Milly Dowler, the hacking of whose voicemails led to the establishment of the inquiry.

The second group was media figures including Rupert Murdoch and former News of the World editors Rebekah Brooks and Andy Coulson.

The third group was politicians such as David Cameron and his predecessor Tony Blair.

What recommendations might it make?

Leveson must decide whether to recommend that the press should be allowed to keep its current system of self-regulation – albeit likely in a stronger form – or whether a new form of statutory regulation backed up by law is necessary.

Cameron’s Government does not in theory have to take up Leveson’s recommendations. Cameron has said that the “status quo is not an option” but there are reports that he might resist statutory regulation due to concerns about press freedom.

What other criminal and civil inquiries are ongoing?

British police have launched three separate criminal investigations.

Under Operation Weeting, which deals with phone hacking, there have been 25 arrests and eight people have been charged, including Brooks and Coulson.

Under Operation Elveden, which involves corrupt payments to officials, there have been 52 Elveden arrests and six people have been charged, again including Brooks and Coulson.

Under Operation Tuleta, which involves computer hacking and privacy breaches, there have been 18 arrests but no one has yet been charged.

The Culture, Media and Sport Committee of Britain’s Parliament also held a series of hearings into the hacking scandal. In a report published last May, it said that Rupert Murdoch was unfit to lead a major global company.