LONDON – Living in self-imposed exile in Russia, former U.S. National Security Agency contractor Edward Snowden may be safely out of reach of the Western powers. But dismayed by the continued airing of trans-Atlantic intelligence, British authorities are taking full aim at a messenger shedding light on his secret files there — the small but mighty Guardian newspaper.

The pressures coming to bear against the Guardian, observers say, are testing the limits of press freedoms in one of the world’s most open societies. Although Britain is famously home to a fierce pack of news media outlets — including the tabloid hounds of old Fleet Street — it also has no enshrined constitutional right to free speech.

The Guardian, in fact, has slipped into the single largest crack in the free speech laws that are on the books: the dissemination of state secrets protecting queen and country in the British homeland. The Guardian, along with The Washington Post, was the first to publish reports based on classified data spirited out of the United States by Snowden.

In the months since, the Guardian has continued to make British officials exceedingly nervous by exposing the joint operations of U.S. and British intelligence — particularly their cooperation in data collection and snooping programs involving British citizens and close allies on the continent.

In response, the Guardian is being called to account by British authorities for jeopardizing national security. The Guardian’s top editor, Alan Rusbridger, is being forced to appear before a parliamentary committee Tuesday to explain the news outlet’s actions. The move comes after British officials ordered the destruction of hard drives at the Guardian’s London headquarters, even as top ministers have taken to the airwaves to denounce the newspaper. Scotland Yard has also suggested it may be investigating the paper for possible breaches of British law.

The government treatment of the Guardian is highlighting the very different way Britons tend to view free speech, a liberty that is seen there through the prism of the public good and privacy laws as much as the right to open expression.

The actions against the paper have led to growing concern in Britain and beyond. Frank La Rue, the U.N. special rapporteur on free expression, has denounced the treatment of the Guardian as “unacceptable in a democratic society.”

Right to know

The Guardian is among the global news outlets thoroughly studying the Snowden files and publishing key parts, a club that in addition to The Washington Post has expanded to include The New York Times and Germany’s Der Spiegel, among others.

U.S. intelligence officials have said publicly that the disclosures endanger national security, and the head of the National Security Agency, Gen. Keith Alexander, has said the federal government needs to a find a way to stop them.

“We ought to come up with a way of stopping it. I don’t know how to do that. That’s more of the courts and the policymakers, but, from my perspective, it’s wrong to allow this to go on,” Alexander told the Defense Department’s Armed With Science blog in October.

The Washington Post does not show stories to U.S. officials in advance of publication, nor does it routinely agree to official requests. But language in some articles has occasionally been modified when officials cited very specific risks to certain intelligence operations and individuals, according to the paper’s executive editor, Martin Baron. A spokeswoman for The New York Times pointed to statements by Executive Editor Jill Abramson in which she said the paper had turned down at least one request by U.S. officials to withhold a story.

Although legal experts say the First Amendment offers stronger protection for the news media in the United States than their counterparts enjoy in Britain, U.S. authorities still have tools at their disposal to limit the disclosure of classified data. Those tools include the 1917 Espionage Act, which federal prosecutors have used to charge Snowden. Nevertheless, U.S. officials have thus far stopped short of the more aggressive tactics being deployed against the Guardian in Britain.

The German government has also taken a relatively hands-off approach. “At Der Spiegel we have not encountered anything similar,” Managing Editor Klaus Brinkbaumer said in an email. “There is no serious pressure.”

In contrast, Rusbridger must explain to the parliamentary committee the paper’s dissemination and handling of the Snowden data.

The move came after Prime Minister David Cameron, speaking on the floor of parliament in October, offered comments that seemed to open the door for the editor’s public grilling.

Scotland Yard, meanwhile, has suggested that it might be investigating the Guardian in connection to the authorities’ continuing probe of David Miranda, the partner of Brazil-based freelance journalist Glenn Greenwald, who formerly worked with the Guardian on its Snowden stories.

In August, British authorities arrested Miranda at Heathrow airport while he was on an information-gathering trip funded by the Guardian. British officials interrogated Miranda for nine hours before confiscating his laptop, cellphone, USB memory sticks and video-game consoles. Miranda was released after being questioned, but the confiscated items remain in official custody.

Pressure from the top

After Miranda’s arrest, Rusbridger disclosed that more-direct pressure had been brought to bear on the paper from the top levels of the British government. In June, he said he was contacted by a senior official in the first of several communications aimed at pressuring the Guardian to destroy hard drives storing data from Snowden that were being kept at the paper’s London headquarters.

Ultimately, Rusbridger said, he agreed to the government’s request for two reasons.

First, because copies of the data were already being safely kept outside Britain, and secondly, because government officials had implied that they would take far more drastic action against the paper if he did not comply.

“Some of this behavior is clearly designed to be intimidatory and/or chilling,” Rusbridger said in an email. “Most of it would be unimaginable in America or parts of Europe. So, yes, I think there are disturbing implications for press freedom in the U.K.”

In the summer, a senior official at the British Embassy in Washington also called Abramson at The New York Times to request the return of Snowden data — a request Abramson has said she denied.

A spokesman at No. 10 Downing Street declined to comment for this article, instead referring to published comments by the prime minister. In October, Cameron, a conservative, took a thinly veiled swipe at the left-leaning Guardian: “I will back the work (security services) do and I will criticize those that make public some of the techniques they use because that is helping our enemies.”

The Guardian has also become the target of a number of other Conservative Party lawmakers. One, Julian Smith, has pointedly sought information from the paper on whether it willfully shipped the names of British secret service agents overseas — an act that could be punishable by law in Britain.

Asked in an email whether the Guardian sent data with names of British agents overseas, Rusbridger did not answer directly. He said: “It’s been apparent to any casual reader since early June that the Snowden documents contain names of some employees of the NSA and GCHQ. We have had no approaches from government or agencies in relation to any names. We have published no names, nor lost control of any material.”

Rusbridger said the paper is keenly aware of a moral responsibility to continue publishing stories in the public interest. “Some people, especially in the U.K., would like newspapers to be gagged or prosecuted,” Rusbridger said. “But . . . without them, be prepared for something much worse.”