British authorities forced the Guardian newspaper to destroy material leaked by Edward Snowden, its editor has revealed, calling it a "pointless" move that would not prevent further reporting on U.S. and British surveillance programmes.

In a column in the paper on Tuesday (August 20), Alan Rusbridger said the "bizarre" episode a month ago and the detention at London's Heathrow airport on Sunday (August 18) of the partner of a Guardian journalist showed press freedom was under threat in Britain.

London's Metropolitan Police defended the detention under an anti-terrorism law of David Miranda, the Brazilian partner of American journalist Glenn Greenwald, saying it was "legally and procedurally sound".

UK Justice Minister Damian Green says the Metropolitan Police was acting under the law.

"That the law is there to protect us from anything that will increase the dangers of terrorism and because these powers are extensive we have an independent investigator. He is talking to the Metropolitan police later today and I suggest we all wait and see what he has to say,." Green said.

Greenwald, who has met Snowden and written or co-authored many Guardian stories about U.S. surveillance of global communications, vowed to publish more revelations and said Britain would "regret" detaining his partner.

Rusbridger said that a month ago, after the Guardian had published several stories based on Snowden's material, a British official advised him: "You've had your fun. Now we want the stuff back."

Rusbridger said the paper was threatened with legal action by the government unless it destroyed or handed over the material from Snowden.

After further talks with the government, two "security experts" from Government Communications Headquarters (GCHQ), the secretive British equivalent of the NSA, visited the Guardian's London offices.

"It felt like a particularly pointless piece of symbolism that understood nothing about the digital age," the Guardian editor said.

Presented by Adam Justice

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