Clodagh Hartley, a Waterford-born journalist, has been cleared by a London jury of making unlawful payments for information to a Revenue and Customs official.
She is the second reporter to be acquitted after a Scotland Yard investigation.
Hartley, who was Whitehall editor for the Sun daily newspaper until she was suspended nearly two-and-a-half years, broke down in tears at Westminster Magistrates' Court when the jury's verdict was announced, saying "Thank you, thank you," to its members.
The Irish journalist faced prosecution after Metropolitan Police detectives working on Operation Elveden investigated emails, mobile telephone text messages and other records linking her to a contact, Revenue and Customs official Jonathan Hall.
Following the jury's decision to acquit Hartley and Marta Bukarewicz, it can be reported that Hall, Bukarewicz's partner, has already pleaded guilty to misconduct in a public office after receiving £17,475 from the Sun.
Giving evidence during the trial, Hartley defended publishing the information received from Hall, including evidence that it had cost £24 million to transfer civil servants from London to Coventry and a department’s decision to spend £1.3 million on self-promotion.
Meanwhile, she said a decision to reveal details of Labour’s last budget in March 2010 showed the pressure that civil servants were under to “spin” tax changes made by the British Government in their dealings with Westminster journalists.
The jury's decision was welcomed by journalists in London, though many expressed unhappiness at the treatment of Hartley by the Sun's owners, the Rupert Murdoch-owned News UK, who handed over information to the police that led to the prosecution.
Editor of the Spectator, Fraser Nelson – who has strongly rejected State regulation of the press – said he was "delighted" by the jury's verdict.
“Helping a whistleblower expose tales of government waste is no crime,” he said.
During the trial, barrister Alexandra Healy said Hartley had been put on trial "for doing her job", adding that she had never hidden her contacts with Hall and all payments made to him had been cleared by senior Sun management.
Her reports had been of public interest and were not “tittle tattle”, she said. Equally, they had caused no harm and the authorities had not launched inquiries to track down where the information before the police started a prosecution.
During the trial, Hartley said she had not known she could be accused of making illegal payments because no journalist had ever been prosecuted under legislation passed in 1906 that left officials open to misconduct in public charges for accepting payments.
Despite her acquittal, Hartley has said she will not return to work at the Sun.