At least 28 journalists might be linked to the escalating phone-hacking scandal that has engulfed News Corp. and triggered a national furor in Britain, a lawyer said in opening remarks at a judicial inquiry that began Monday.

Robert Jay, the main counsel for the Leveson Inquiry into media ethics, said there was “at the very least a thriving cottage industry” of phone hacking at News of the World, a Rupert Murdoch-owned tabloid that was closed in July after startling allegations that the paper had hacked into the voice mails of a teen murder victim.

The outlined scale of illicit tactics allegedly used by the publication is dramatically greater than previously thought and flies in the face of the tabloid’s long-held stance that the hacking was confined to one “rogue” reporter.

British Prime Minister David Cameron ordered the inquiry in July as the scandal swept through the upper echelons of Britain’s media, police and political establishments, and led to the dramatic closure of News of the World.

The wide-ranging inquiry, which will examine the culture, practices and ethics of the press, is led by Brian Leveson, a respected senior appeal court judge.

During his opening remarks, Jay said the names of more than two dozen employees at News International, News Corp.’s British newspaper arm, were found in the 11,000 pages of notes seized from Glenn Mulcaire, a private investigator paid by News of the World.

Mulcaire scribbled first names in the top left-hand corner of his notes, the inquiry was told, including the name “Clive,” presumably referring to Clive Goodman, a former royal editor for the tabloid who was briefly jailed alongside Mulcaire in 2007.

After Clive, the next four most common “corner names” made 2,143 requests for information, the inquiry was told.

Mulcaire’s notebooks also contained the name “The Sun” and another that might relate to the “Daily Mirror,” Jay said, suggesting that the scope of the alleged illicit activities might extend to other publications. He also said police suspect that hacking at News of the World might have started as early as May 2001 and continued until 2009.

Leveson said that at the heart of the inquiry is “one simple question: Who guards the guardians?”

Fleet Street is bracing for a rocky road as the inquiry is set to hear testimony from journalists, police officials, politicians and victims of phone hacking.

Recommendations by Leveson are expected by September 2012, and they could result in dramatic changes in the way Britain’s newspaper industry is regulated. Some critics have called for journalists to be licensed.

Although a roster of witnesses has not been released, more than 50 alleged phone-hacking victims will be legally represented at the inquiry, including the family of Milly Dowler, a 13-year-old murder victim; “Harry Potter” author J.K. Rowling; and actors Hugh Grant and Sienna Miller. The first alleged hacking victim in the case will be called next Monday.

Leveson said the inquiry would monitor media coverage of its witnesses, warning that any bullying or unfair treatment could “be relevant to my ultimate recommendations.”

He stressed that freedom of the press was “fundamental” to a healthy democracy but said that freedom “must be exercised with the rights of others in mind.”

Seeking to get in front of any tighter media restrictions that might result from the inquiry, many editors have spoken out about ways to change the industry.

In a rare public appearance last month, the Daily Mail’s top editor, Paul Dacre, argued for a beefed-up self-regulatory body and called for an industry ombudsman with power to investigate and impose fines — an idea that has gained some traction among fellow editors. He also introduced a corrections column in the paper.

The inquiry held seminars in September and October to set up the context for the hearings. Not all of it was comfortable listening. Richard Peppiatt, a former freelance journalist at the Daily Star, a down-market tabloid, submitted a gripping account of his reporting days, saying: “I can probably count on fingers and toes the amount of times I genuinely felt I was telling the truth.”

The inquiry will also investigate illicit tactics used by British media organizations, but only after the police investigation is finished, which could take years.

Leveson is being assisted by six others, who were appointed by the prime minister: David Bell, the former chairman of the Financial Times; Shami Chakrabarti, director of Liberty, a civil liberties campaign group; David Currie, former director of Ofcom, the broadcast regulator; Elinor Goodman, former political editor of Channel 4 News; George Jones, former political editor at the Daily Telegraph; and Paul Scott-Lee, former chief constable of the West Midlands police force.

The panel has been criticized for not including representatives of the tabloid press.

The sessions are being streamed live online at