A lawyer for phone-hacking victims claimed today that the illegal interception of voicemails was "much more widespread" than just the News of the World.
Mark Lewis told the Leveson Inquiry into press standards that hacking the phones of celebrities and other people in the news was "too easy to do" for journalists.
He suggested that reporters, at least initially, thought of the practice as no worse than driving at 35mph in a 30mph zone.
Mr Lewis said the News of the World was the paper caught out hacking phones because its private detective, Glenn Mulcaire, kept such detailed records.
He told the inquiry: "In a way, I feel sorry for the News of the World, or certainly the News of the World's readers.
"Because it was a much more widespread practice than just one newspaper.
"It was just simply that their inquiry agent, Glenn Mulcaire, had written things down and kept the evidence.
"The fact that evidence doesn't exist in written form doesn't mean to say that the crime didn't happen."
Mulcaire was jailed along with the News of the World's former royal editor Clive Goodman in January 2007 after they admitted intercepting voicemail messages left on phones belonging to royal aides.
Mr Lewis, whose clients include the family of murdered schoolgirl Milly Dowler, whose phone was hacked by Mulcaire, said he believed illegal voicemail interception was widespread because there was no other means for journalists to get certain information.
"It is evidence-based conclusions, certainly on a civil basis, of what I am being told by clients and taking instructions from them as to whether or not stories are written that could not have got to newspapers in any other way," he said.
"Phone hacking might only give two or three parts of the jigsaw, but it might suggest that so-and-so a person will be at such an address, or so-and-so a person is speaking to somebody.
"Or the journalist then knows which address to go to, or who they are speaking to or who they are having a relationship with."
He added: "What phone hacking, simply remote voicemail interception, enabled people to do was just to pry on things.
"It was too easy to do. I mean, journalists found it too easy to do. And therefore I don't think they necessarily thought of it as any worse - certainly at the beginning - than driving at 35mph in a 30mph zone."
Mr Lewis also told the inquiry that News of the World journalists wrongly concluded Professional Footballers Association (PFA) chairman Gordon Taylor was having an affair after hacking his phone.
He said the paper's reporters misinterpreted a voicemail message from a woman thanking Mr Taylor for speaking at her father's funeral.
Mr Lewis told the inquiry that a photographer working for the News of the World took a picture of Joanne Armstrong, then the PFA's in-house solicitor, having lunch with Mr Taylor in the mid-2000s.
The lawyer wrote to the Sunday tabloid ordering it not to publish the photograph and threatening to apply for an injunction.
He said the News of the World's lawyer, Tom Crone, replied saying the paper would not run the story but refusing to pay damages or costs because it was obtained through "proper journalistic inquiries".
Mr Lewis rejected the explanation, telling the inquiry: "It just wasn't a proper legitimate investigation. It was a phone had been hacked in order to get that story."
Mr Taylor had spoken at the funeral of Ms Armstrong's father and she left a message on his phone the next day saying, "Thank you for yesterday, you were wonderful", the inquiry heard.
Mr Lewis said: "The tabloid journalist who knew of that message added two and two and made 84. They couldn't possibly conceive of any other explanation.
"If it hadn't been so sad, it would have been funny."
Mr Lewis said he realised Mr Taylor's phone had been hacked after seeing a news report about Goodman and Mulcaire pleading guilty to illegally intercepting the voicemail messages of royal aides.
Mulcaire also admitted hacking the phones of high-profile non-royals, including Mr Taylor, publicist Max Clifford, MP Simon Hughes and supermodel Elle Macpherson.
Mr Lewis said: "As far as I was concerned it was a lightbulb moment, a eureka moment. That is how he got the story, because the story just wasn't true."
Mr Lewis went on to describe the reaction of News of the World publisher News Group Newspapers after Mr Taylor launched a claim against the paper.
He was told the publisher's lawyer Tom Crone would come and see him, which he claimed was not just a surprise but also "a very big giveaway".
He said: "The fact he was coming to see me suggested they had something to hide."
But when he put to Mr Crone the figure of £250,000 as a possible settlement fee for Mr Taylor, Mr Crone "just got up and left", he said.
However, he went on, the company's position changed when he presented its solicitors with the "for Neville" email, which contained transcripts of hacked messages from Mr Taylor's mobile phone and was apparently intended for chief reporter Neville Thurlbeck.
"That's when negotiations started," he said. "It was one of those occasions when you have to do the smoking gun."
The publisher made a settlement offer of £50,000, which "quickly went up to £100,000", he told the inquiry.
A "flurry of activity" on the publisher's part eventually culminated in an offer of £250,000, he said.
The final figure was £425,000 for damages plus costs, the inquiry heard.
Mr Lewis also claimed that a Metropolitan Police officer had promised to help him bolster the case he was bringing for Mr Taylor.
He said Detective Sergeant Mark Maberly told him during the course of a conversation: "You are not having everything but we'll give you enough on Taylor to hang them."
DS Maberly denies this and disputes that he used the words "hang them" as opposed to "load your gun", according to evidence submitted to the inquiry by Mr Lewis.
In the wake of the Taylor case, two further claimants wanted Mr Lewis to take similar actions for them but Mr Taylor was not happy about it, the inquiry heard.
"He (Mr Taylor) said I had entered into an agreement with him that I wouldn't act for anyone else ever on anything that he had had to do with," Mr Lewis said.
"It was something that had never been discussed with Mr Taylor."
Daily Mail publisher Associated Newspapers was dragged into the frame too when Mr Lewis claimed he had been handed a copy of a CD in which Mr Mulcaire was coaching another man how to hack.
"(The man) was working for a newspaper which at that time belonged to the Associated group," he said.
David Barr, counsel to the inquiry, named the paper as the London Evening Standard.
Asked how Associated Newspapers reacted during his dealings with them, Mr Lewis said he had received a phone call from the company's in-house solicitor, Liz Hartley, in which she appeared to be warning him off.
"She said (Daily Mail editor-in-chief) Paul Dacre wouldn't hesitate to sue me if I suggested the Daily Mail was involved in phone hacking," he told the inquiry.
"I think that was supposed to be a general warning."