Charges against nine journalists accused of making illegal payments to public officials have been dropped by the Crown Prosecution Service.
Nine of the 12 journalists awaiting trial under Operation Elveden will not be prosecuted, after an urgent review.
The Society of Editors called the investigation and prosecution of journalists an "incredible fiasco".
But the director of public prosecutions defended the decisions to prosecute the journalists.
Duncan Larcombe, royal editor at The Sun, said the investigation and prosecutions had been "politically motivated" and "without justification".
Those who no longer face prosecution under Operation Elveden - the Metropolitan Police investigation into alleged inappropriate payments to police and public officials - include former News of the World editor Andy Coulson.
The CPS said it had decided to continue with the prosecutions of three Sun journalists; Jamie Pyatt, Chris Pharo and - in a separate case - Anthony France.
All three are accused of paying police officers. Seven public officials will also continue to face charges, the CPS said.
Mr Coulson faces a separate trial in Scotland - due to start next month - over allegations of perjury.
Those who will no longer face charges over alleged payments to officials are:
- Mr Coulson
- Clive Goodman, ex-News of the World royal editor
- Greig Box Turnbull, former Daily Mirror journalist
- Stephen Moyes, former Daily Mirror and News of the World journalist
- Ryan Sabey, ex-News of the World royal reporter
- Vince Soodin, Sun journalist
- Ben O'Driscoll, Sun journalist
- Graham Dudman, Sun journalist
- Lucy Panton, News of the World crime reporter
The announcement comes after three journalists were found not guilty of illegally paying public officials at London's Old Bailey.
Ex-Daily Mirror reporter Graham Brough and the Sun's Neil Millard and Brandon Malinsky were cleared of conspiring to commit misconduct in public office.
Sun reporter Tom Wells was also cleared of two counts. The jury was then discharged after failing to agree verdicts on a third charge against Mr Wells and one against ex-immigration officer Mark Blake.
The CPS has yet to announce whether it will seek a retrial on those counts.
BBC legal correspondent Clive Coleman said the practice of paying public officials for information had been largely ignored or tolerated "for decades" but the phone-hacking scandal had been a "game changer".
The Met Police has spent more than £11m on Operation Elveden, which last year had 56 dedicated officers and staff.
Police have made 87 arrests and interviewed 56 suspects under caution.
Dozens of those investigated have been journalists, 29 of whom have been charged. Of those, 13 have been cleared following trials.
But BBC home affairs correspondent Danny Shaw said the Elveden strategy "started to unravel" in March, when four Sun journalists - John Kay, Geoff Webster, Fergus Shanahan and Duncan Larcombe - were acquitted.
The CPS launched its review of the outstanding Operation Elveden cases after the Court of Appeal last month ruled out a retrial of News of the World reporter Lucy Panton.
Lord Chief Justice Lord Thomas found the jury in her trial should have been directed that there must be serious harm to the public interest for an offence of misconduct in public office to be proved.
He also gave ex-News of the World reporter Ryan Sabey leave to appeal against his conviction.
Mr Sabey remains the only journalist to be convicted by a jury under Operation Elveden, although one other pleaded guilty.
'Drug dealers and terrorists'
Bob Satchwell, executive director of the Society of Editors, said Operation Elveden had been an "incredible fiasco" which had caused "huge reputational damage" to the British press and "even greater human costs" to journalists who had faced prosecution.
He said journalists had been "treated like drug dealers and terrorists" for offences which would have carried shorter sentences than the time they spent awaiting trials.
Mr Larcombe said the operation was "an affront to a democratic country".
He called for Director of Public Prosecutions Alison Saunders and Met Police Commissioner Sir Bernard Hogan-Howe to resign.
But Ms Saunders rejected suggestions the CPS had been too quick to charge the journalists
"This wasn't about whistle blowing, it was about public officials engaging in corrupt behaviour, selling stories over a period of time... I think we made the right decisions in accordance with the guidance that we had issued," she said.
The CPS said the Court of Appeal ruling about misconduct in public office cases would be reflected in updated guidance for prosecutors who have to decide whether suspects should face charges.
It said the fresh guidance would also be applied in five cases where suspects are currently under investigation and may face prosecution.