Jon Snow, the Channel 4 news anchor, has launched a scathing attack on Daily Mail publisher, Associated Newspapers, claiming it has a "pernicious" and sometimes "mendacious" agenda to undermine people in public life.

Snow told the Leveson inquiry on Monday afternoon that the publisher of the Daily Mail and Mail on Sunday was worse than News International's titles and had an agenda that undermined politicians and others.

"There is something more insidious about Associated Newspapers and very possibly they will go after me for saying so," he said. "I believe they have an agenda for trying to undermine or wreck the careers of individual people in public life and I think that is unhealthy."

Snow added that the private lives of people in public life are largely irrelevant to readers and they should be allowed to "stand or fall by what they achieve or fail to achieve".

He said: "If it was found that the Bishop of Canterbury was frequenting Soho that would be of public interest. It goes beyond that – people who have quite modest, perhaps, roles in public life are undermined. It is as I say pernicious and I think at times mendacious."

This is the second time in the inquiry the word "mendacious" has been used in relationship to Associated Newspapers.

Last year the publisher attacked Hugh Grant's evidence as "mendacious", infuriating Lord Justice Leveson, who thought its press statement issued immediately after the actor's testimony would discourage others from coming forward to appear before the inquiry.

Snow's use of the word is likely to enrage management at Associated but is unlikely to be contested.

He prefaced his remarks by recounting the frustrating time he had with the Mail on Sunday over a five-page article it wrote about his private life, which he said the paper later confessed was not true. Later he said he had not intended to bring the incident up but it "burned a hole in my soul".

Snow said the paper's apology after his complaint was "pathetic", amounting to just one and a half inches on page two, the so-called graveyard slot in the newspaper.

The paper "right up to publication" fought over whether a passport-sized photo of him would be used or not, he added.

Snow told Lord Justice Leveson that editors of newspapers, in the same way as TV news programmes, should be forced to carry apologies of equal prominence to the original offence.

"What is so shameful about being wrong? We are all human beings? Let's admit it. There is nothing exceptional about an editor. Editors are human beings. They can apologise," he said.

He also used his testimony at the Leveson inquiry to criticise the Sun for lampooning the England football manager just because he "can't roll his Rs".

He told Leveson: "How does that encourage people to make the extra effort to be in public life?"

On the separate issue of media proprietors, Snow, one of the country's leading journalists, said he regretted not asking enough questions about secret deals Rupert Murdoch may have cut in Downing Street.

"We were well aware about Rupert Murdoch's movements, either at the back or the front but not always and that should have raised a bit of an alarm bell," he added. "We used to laugh up our sleeves and say this is what the Italians did, now we do it. It's amazing."

Also appearing at the inquiry on Monday afternoon, the political editor of the Mail on Sunday, Simon Walters, was not asked about an article he co-wrote claiming that Leveson had phoned the cabinet office threatening to quit over education secretary Michael Gove's comments that the inquiry was creating a "chilling atmosphere" for freedom of expression.

The appeal court judge told the inquiry that Walters had been summoned to give evidence in April, well before the article in question was published in June.

Walters told the inquiry that he had it on good authority that Rupert Murdoch was given "privileged information" such as a "reading on certain issues, for example the Iraq war".

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