The police were blocked from seizing television footage yesterday, in a landmark High Court ruling to protect "the neutrality of the press".
Judges quashed orders obtained by Essex Police that forced several TV companies to hand over images shot during the violent evictions of travellers at the Dale Farm site near Basildon last October.
The BBC, ITN, BSkyB and Channel 5 were among those to challenge the order, insisting it was simply a "fishing expedition" and threatened the safety of journalists by turning them into police informants.
Yesterday judges at the High Court ruled that Judge Gratwicke, who made the orders at Chelmsford Crown Court in February, had gone wrong in law. Laying down guidelines, Lord Justice Moses and Mr Justice Eady, said the police were entitled, under the 1984 Police and Criminal Evidence Act (Pace) to seek material "likely to contain evidence" of offenders committing acts of violence. But they warned "the neutrality of the press" must be protected.
Applications had to be backed by "clear and specific evidence" that the material would be "of substantial value" in seeking to prosecute violent offenders. In the Dale Farm case, there was inadequate evidence, the judges ruled. The police wanted access to "a vast amount of film" for "a merely speculative exercise".
Fran Unsworth, the BBC's head of news gathering, said: "Journalists must not be seen as evidence gatherers."