Guardian newspaper editor Alan Rusbridger has revealed that British authorities threatened to censor his team's reporting on surveillance by the state.
Rusbridger says British officials told him that documents from the whistleblower Edward Snowden should be destroyed or handed back and that they would use the courts to enforce their position.
The British government is already facing questions over why the under anti-terrorism laws.
Rusbridger wrote on the Guardian website that UK officials have asked him to stop reporting news of government internet surveillance systems.
"During one of these meetings I asked directly whether the government would move to close down the Guardian's reporting through a legal route - by going to court to force the surrender of the material on which we were working," he said in a statement.
He says two months ago he was contacted by a senior government official who said he represented the views of prime minister David Cameron.
Rusbridger says during a "steely" yet "cordial" meeting, the official demanded the return or destruction of documents obtained from Mr Snowden.
"The official confirmed that, in the absence of handover or destruction, this was indeed the government's intention," Rusbridger said.
"Prior restraint, near impossible in the US, was now explicitly and imminently on the table in the UK."
The documents show the National Security Agency (NSA) is trawling through vast amounts of private internet communication via its PRISM and XKeyscore systems.
The revelations have caused much embarrassment for Western nations and launched a debate about the balance of national security, the freedom of speech and privacy and civil liberties.
Rusbridger says that about a month ago, a UK official, referring to the Snowden documents, told him: "You've had your fun. Now we want the stuff back."
He says there were further meetings with "shadowy Whitehall figures" who again demanded the return of the Snowden material.
He says one official then told him: "You've had your debate. There's no need to write any more."
Rusbridger says two Government Communications Headquarters (GCHQ) security experts oversaw the newspaper's destruction of the digital copies.
"And so one of the more bizarre moments in the Guardian's long history occurred," he said
"With two GCHQ security experts overseeing the destruction of hard drives in the Guardian's basement just to make sure there was nothing in the mangled bits of metal which could possibly be of any interest to passing Chinese agents.
"'We can call off the black helicopters', joked one as we swept up the remains of a MacBook Pro."
Rusbridger confirmed that the Guardian will keep reporting the story, likely via backups of the documents, just not from London.
The Guardian's decision to publicise the threats is the latest step in an escalating battle between some media companies and western governments.
British authorities were already facing questions over the detention of Guardian journalist Glenn Greenwalk's partner David Miranda under anti-terrorism legislation.
The chairman of the home affairs select committee Labour MP Keith Vaz says the detention was "extraordinary" and he is seeking an explanation.
"Has the period of detention of nine hours been justified and has the confiscation of personal items belonging to Mr Miranda, has all this been justified?" he said.
"So what we need to do is establish those facts and then perhaps later on, look at this legislation to see why is it so wide that it has ended up with someone who is frankly not that closely connected with Mr Snowden."
Greenwald says the incident has emboldened not intimidated him, and he will now be more aggressive, not less in his reporting.
Former NSA contractor Mr Snowden received asylum in Russia on August 1, after spending more than five weeks stranded in a Moscow airport avoiding extradition to the US.
He is wanted by Washington on espionage charges linked to his media disclosures about the secret details of US surveillance programs.