Mr Brown said he knew the names of further victims as he told MPs he was not speaking for himself but for the families of terrorist victims and soldiers killed in war, as well as the family of Milly Dowler.
He told MPs he wanted to defend the freedoms of the press but reforms were needed.
Mr Brown told MPs: "At all times I have defended the right of the press to expose any wrongdoing wherever it is found and to speak truth to power however uncomfortable it is and indeed was for me.
"It is my judgment that we should reform but never undermine something so fundamental to our ordered liberty, our twin commitments to both the freedom of the information and a free press."
He added: "Many, many wholly innocent men, women and children who at their darkest hour, at the most vulnerable moment of their lives, with no-one and nowhere to turn, found their properly private lives, their private losses, their private sorrows, treated as the public property of News International.
"Their private and inner most feelings and their private tears bought and sold by News International for commercial gain."
Mr Brown added: "Amassed against these guiltless victims and against a succession of other victims of crime, whose names I know about and have seen, and have yet to be made public, this systematic use of base and unlawful methods ... are not the misconduct of a few rogues or a few freelancers, but I have to say law-breaking often on an industrial scale, at its worst dependent on its links with the British criminal underworld."
Mr Brown said the revelations of the last ten days had given rise to "new crimes with new names", such as blagging, hacking and Trojan emails which can break in to computers and not just phones.
Tory MPs repeatedly rose to their feet and tried to interrupt Mr Brown but Labour MPs shouted: "Sit down!"
The former Prime Minister branded News International "a criminal media nexus" which "claimed to be on the side of the law-abiding citizen" but in fact stood "side-by-side with criminals against our citizens".
He went on: "Others have said that in the behaviour towards those without a voice of their own, News International descended from the gutter to the sewer.
"The tragedy is that they let the rats out of the sewer."
Mr Brown said when he moved into 10 Downing Street in June 2007 he had "no knowledge of the systematic criminality within News International".
He said his priority was to "unite the country, not divide it, to bring people on board not to pick fights with them, to strive to create the broadest coalition of churches for our nation".
He did not want to "wilfully make an enemy of anyone" but "seek to build bridges with members of the public and the Press".
Mr Brown, who volunteered to give evidence to any inquiry investigating hacking, denied accusations the relationship between his Government and News International broke down during the Labour Party conference in autumn 2009 when the media group's flagship title The Sun ditched its support for the party.
He quoted a string of negative headlines such as "Brown Killed My Son", "Doctor Evil" and "The Betrayer of Britain" proving he was not in league with News International's executives.
"The relationship between News International and the Labour administration I led was from start to finish neither cosy nor comfortable," said Mr Brown.
"It has been said the relationship between News International and the Government of the day changed only because in 2009 News International suddenly decided to formally oppose Labour.
"The relationship with them was always difficult because Labour opposed their self-interested agenda for the future."
He defended his decision not to set up an inquiry when allegations of phone hacking resurfaced in 2009.
"During the last year of our Government information became public suggesting the hacking of phones and indeed computers went far beyond one rogue reporter and one rogue newspaper," Mr Brown said.
"But already in August 2009 Assistant Commissioner (John) Yates of Scotland Yard had taken only eight hours - less time than he spent dining with the people he should have been investigating - to pre-emptively reject a further police inquiry."
Mr Brown said he asked civil service chief Cabinet Secretary Sir Gus O'Donnell to agree to launch a judicial inquiry.
"Far from the so-called cosy relationship with News International that would have meant doing nothing, my answer to what appeared to be News International's abuse of press freedom was a full judge-led inquiry to meet growing public concern," said Mr Brown.
But he quoted official advice he received rejecting an inquiry which said: "There was a media culture permissive of unlawful activities and deliberate obfuscation by News International.
"The (Culture, Media and Sport) select committee did not believe the practices were still continuing and thus it did not meet the test of urgent public concern.
"Time had elapsed and evidence may have been destroyed, the News of the World and individuals had already been punished by resignations and jail terms, there was no evidence of systematic failure in the police - and anyway all the decisions had been checked with the Crown Prosecution Service.
"Targeting the News of the World would have been deemed to be politically-motivated because it was too close to the General Election and would inevitably have raised questions over the motivation and urgency of an inquiry."
