Media organisations have won a High Court battle over police orders to give up film of the evictions from the traveller site at Dale Farm in Essex.
The police claimed they needed the footage from organisations like the BBC and BSkyB to pursue prosecutions.
Police said they were supporting court orders granted to Basildon Council.
But the High Court said police had failed to make a sufficiently strong case and broadcasters viewed the orders as a "fishing expedition" for evidence.
The BBC, Independent Television News, BSkyB, Channel 5, Hardcash Productions and freelance video journalist Jason Parkinson joined forces to oppose the orders.
Their lawyers said the media risked becoming seen as "coppers' narks" if they were forced to comply.
Interference with rights
The footage was shot during the operation to evict travellers from the site near Basildon last year.
Filmed on 19 and 20 October, it includes scenes of violence as bailiffs dismantled barricades.
The production orders were originally made by Judge Gratwicke at Chelmsford Crown Court in February, but have now been quashed by Lord Justice Moses and Mr Justice Eady.
Gavin Millar QC, for the media organisations, said police were increasingly seeing such orders as a "convenient way to access evidence that may be used in court".
In a written judgement, Mr Justice Eady said it was difficult to dispute there was a real public interest in tracing people involved in public disorder or violence.
But he said that had to be set against the level of interference with the media's right to freedom of expression under Article 10 of the European Convention on Human Rights.
Essex Police had to demonstrate that the "degree of interference" and the wide scope of the production order was "necessary and proportionate", he said.
However, there was "nothing to justify any such conclusion".
"Because the cupboard was bare when it came to demonstrating that the material would be of substantial value to the police investigation, the claimants were denied a fair opportunity to demonstrate to the (Chelmsford) court why much, if not the totality, of their material was unlikely to be of any assistance."
Mr Justice Eady said disclosure orders "can never be granted as a formality", and while police should not be discouraged from seeking to obtain material in future, "it is not easy to do so and it should not be easy".
The fact that Judge Gratwicke was unable to justify the order he made "stemmed from the inadequacy of the evidence and the grounds advanced by the police", Mr Justice Eady added.
ITN chief executive John Hardie said: "This landmark decision is a legal recognition of the separate roles of the police and independent news organisations.
"We fought this case on a matter of principle - to ensure that journalists and cameramen are not seen as agents of the state, and to protect the safety of our staff.
"The requests from Essex Police didn't relate to specific incidents of serious criminality and amounted to no more than a fishing expedition to see what footage ITN and other news organisations held on the Dale Farm evictions."
Fran Unsworth, the BBC's head of newsgathering, said: "This is a significant ruling which reinforces the independence of news organisations from the police.
"Journalists must maintain their independence, must not be seen as evidence gatherers and must not have their safety compromised."