A judge has dismissed Gina Rinehart's bid to force a journalist to divulge source material for articles about her bitter family feud, saying the billionaire's tactics were "oppressive".
In a landmark judgment by WA Supreme Court Justice Janine Pritchard, she set aside a subpoena served on Gold Walkley winning reporter Steve Pennells, which could have landed him in jail.
Pennells and his employer, The West Australian newspaper, had been fighting Ms Rinehart's legal demands for more than 18 months.
But in a resounding win, Justice Pritchard said the subpoena should be set aside "on the ground that it is oppressive and an abuse of process".
Justice Pritchard also came down firmly on the side of WA's journalistic 'Shield Laws', which lawyers for Mr Pennells argued would have been breached if Ms Rinehart was granted access to sources.
"If the Shield Laws do not apply in respect of the production of documents under a subpoena, the very protections the Shield Laws are designed to provide could be significantly undermined, if not rendered nugatory," Justice Pritchard said.
Pennells has written a series of articles on the bitter family legal stoush between Australia's richest person and most of her children.
Ms Rinehart has also issued an identical subpoena to Fairfax journalist Adele Ferguson, who penned an unauthorised biography of the Hancock Prospecting supremo.
After being given an advanced copy of the judgment yesterday, lawyers for Ms Rinehart argued the ruling be kept under wraps on legal grounds.
But that application was denied by Justice Pritchard.
In court to hear the judgment, Pennells said it was a win for him, and journalism in general.
"Having this over your head for 18 months is a big weight on your shoulders," he said.
"Not only it is a weight off my shoulders, but it has enshrined in the judgment the things that we hold sacred in journalism.
"The right to protect sources, the right for people to come to us and tell us things and not be worried they can use the courts to try and get at them."
Media, Entertainment and Arts Alliance federal secretary Christopher Warren said the judgment should now prompt uniform shield laws across the country.
"There is a deficiency in Australian shield laws if powerful people can still threaten to drag journalists through court procedures in an effort to disclose information," Mr Warren said.
And Brett McCarthy, editor of The West Australian, said taking on Ms Rinehart in court had been worth it.
"It is a spectacular win for journalism, and there is some very strong stuff that backs up Shield Laws, and the judge's decision will protect journalists around the country," Mr McCarthy said.
"We would fight for them no matter who brought that action against us."