When David Shayler was on trial, he wanted to introduce evidence that MI6 had paid an Al Qaeda cell a wodge of dosh to bump off Gadaffi. PII certificates were signed which forbade him from introducing that evidence, but which apparently (I'll be the first to say I have no particular legal expertise!) also extended to the Press publishing the allegations. The observer had already published them, and was forced to "unpublish". They later wrote:
Startling revelations by French intelligence experts back David Shayler's alleged 'fantasy'about Gadaffi plotBritish intelligence paid large sums of money to an al-Qaeda cell in Libya in a doomed attempt to assassinate Colonel Gadaffi in 1996 and thwarted early attempts to bring Osama bin Laden to justice.
<snip>
During the Shayler trial, Home Secretary David Blunkett and Foreign Secretary Jack Straw signed Public Interest Immunity certificates to protect national security. Reporters were not able to report allegations about the Gadaffi plot during the course of the trial.
These restrictions have led to a row between the Attorney General and the so-called D-Notice Committee, which advises the press on national security issues.
The committee, officially known as the Defence, Press and Broadcasting Advisory Committee, has objected to demands by the prosecution to apply the Official Secrets Act retrospectively to cover information already published or broadcast as a result of Shayler's disclosures.
On top of this, you can see at cryptome reproductions of some gagging orders issued to the Observer reporter Martin Bright, which related to the Shayler case:
http://cryptome.org/r-v-bright.htmThese call themselves injunctions. One of them says:
PENAL NOTICE
2. If you, the defendant, disobey paragraphs (1) or (2) of this Order you may be found guilty of contempt of court and may be sent to prison or fined or your assets may be seized.
INTRODUCTION
3. A without notice application was made on 1 November 2002 by Counsel for Her Majesty's Attorney General ("the Claimant") to the Judge who heard the application in private (having had regard to Article 6(1) of the European Convention on Human Rights) save for the making of this Order.
4. The application was supported by information provided to him by Counsel for the claimant and the Judge accepted the undertakings in Schedule 2 to this Order.
5. As a result of the application.
IT IS ORDERED THAT:
(1) The Defendant be restrained until trial [handwritten: the conclusion of the current trial of DMS [i.e. David Michael Shayler] or any retrial] or further Order whether by himself, his servants or agents or otherwise howsoever from further publishing or causing or permitting to be published or disclosed or instruction or encouraging any other person further to publish or disclose in any way whatsoever, including, for the avoidance of doubt, publication or disclosure on the Internet, the article written by the Defendant entitled, 'MI6 Hire Al Qaeda Men to Kill Gaddafi: Ex-Official" and published on 30 October 200 in Pakistan in the Dawn newspaper and on the Internet on the Dawn newspaper's Interned site or any part thereof.
The injunction also forbids Bright reporting anything said by Shayler in regard to his former employment.
Ok, this isn't a PII certificate. But it shows, perhaps, that PII certificates can give rise to gagging orders on cognate matters - so perhaps "PII cert" is just being used as shorthand for this sort of arrangement.
In the above, the Observer were allowed to publish the allegation after the conclusion of the trial. But perhaps in the other case there's some further condition added in to a PII-related injunction that still applies.
On the other hand, the Guardian could just be part of The Conspiracy! ;-)