When the editor of The Guardian, Alan Rusbridger, published an op-ed yesterday on the arrest of Glenn Greenwald’s partner David Miranda at Heathrow airport on Sunday, Rusbridger waited until paragraph nine before describing the heavy-handed response of the British government to the Snowden leaks.

That the paper would be under pressure from the highest levels of government to shut down the story and that GCHQ goons would oversee the destruction of hard drives in The Guardian’s basement, would surely have warranted detailed coverage at the time of these events, accompanied by at least one strongly-worded editorial. So why did the paper’s editor wait two months to say anything, and why did he partially bury the story by reporting on it in the middle of the outcry following Miranda’s detention?

The short answer is: I don’t know. But the likely explanation is that The Guardian did not believe it was at liberty to disclose the latest example of Britain’s operation as a police state.

Prior to the incidents Rusbridger recounted, the Ministry of Defence had already moved to silence the press on June 7 by issuing a DA-Notice.

This is Britain’s Orwellian system of “guided media self-regulation”. Secret notices are issued advising newspaper editors when they should keep their mouths shut through a “voluntary” system which, if not followed, places an editor at risk of prosecution. It’s a bit like the friendly advice a Mafia enforcer gives someone on how to avoid getting his kneecaps shattered.

In the age of the internet, censorship is clearly an anachronism, but the fact that information might be widely available outside the UK is not in the eyes of the Ministry of Defence a justification for the same information to be disseminated further by British publications. The DA-Notice System cryptically advises: “just because something is on a foreign website, it does not necessarily mean that it has immediately been widely seen.” Which seems to imply, for instance, that just because a story appears in the New York Times, that doesn’t justify The Guardian covering it too.

On June 7, Jeff Stein reported:

The June 7 “DA-Notice,” or Defence Advisory Notice, which was itself confidential, accepted that the U.S. National Security Agency was sharing information gleaned from the surveillance programs with its British counterparts, and said UK intelligence organizations were worried about revelations of their own roles in the programs.

“There have been a number of articles recently in connection with some of the ways in which the UK Intelligence Services obtain information from foreign sources,” said the notice issued by the Defence Advisory Committee, a joint body with media organizations.

“Although none of these recent articles has contravened any of the guidelines contained within the Defence Advisory Notice System, the intelligence services are concerned that further developments of this same theme may begin to jeopardize both national security and possibly UK personnel,” it said.

The notice itself was marked “Private and Confidential: Not for publication, broadcast or use on social media.”

It warned British media not to publish information on “specific covert operations, sources and methods of the security services, SIS and GCHQ [the NSA’s British counterpart], Defence Intelligence Units, Special Forces and those involved with them, the application of those methods, including the interception of communications and their targets; the same applies to those engaged on counter-terrorist operations.”

British news organizations are concerned about the tenor of the advance warning.

“They’re sending out a notice saying nothing’s been published that damages national security but we’re concerned the press might (and on the back of developments in the US, no less),” said a media source.

The worry is that British authorities may be preparing to pursue reporters through the courts if they publish details on UK participation in the massive US electronic surveillance programs, code-named “PRISM” and “BLARNEY,” according to a report in The Washington Post.

At Columbia Journalism Review, Ryan Chittum writes:

Prior restraint is the nuclear option in government relations with the press and unfortunately, the British don’t have a First Amendment. But Rusbridger, having gone through the fire with Wikileaks, was prepared for that. The paper’s journalism is mostly being done in New York and the Snowden documents are dispersed in other countries.

Combine Rusbridger’s revelations with news of the detention of Greenwald’s partner David Miranda by UK authorities and you have a DEFCON 2 journalism event.

Miranda was serving as a human passenger pigeon, shuttling encrypted files on USB drives between filmmaker Laura Poitras and Greenwald because, as the whole world now knows, the Internet is fully bugged by the US and UK governments. So the UK, using an anti-terrorism statute, arrested Miranda on arrival at Heathrow, interrogated him for 9 hours, threatened to arrest him, and took his stuff. The war on whistleblowers has now escalated to disrupting journalists’ communications.

In light of Rusbridger’s disclosures, it’s even clearer that the detention of Miranda is part of an attack on American journalists authorized at the highest levels of the British government, and it’s an attack that is at the very least implicitly backed by the Obama administration.