Katherine Gun's prosecution seemed to be stopped because her defence was going to demand the production of documents showing she was attempting to stop a worse crime:
During today's hearing, the charge was formally put to her that between January 30 and March 2 last year she disclosed information relating to security or intelligence contrary to the Official Secrets Act of 1989.
Then after she pleaded not guilty, prosecutor Mark Ellison told the court the case would not go ahead. He said: "The prosecution offer no evidence against the defendant on this indictment as there is no longer sufficient evidence for a realistic prospect of conviction. It would not be appropriate to go into the reasons for this decision."
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She argued the alleged disclosures exposed serious wrongdoing by the US and could have helped to prevent the deaths of Iraqis and British forces in an "illegal war".
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For her defence, she had planned to seek the disclosure of the full advice from the attorney general, Lord Goldsmith, on the legality of the war against Iraq, which could have been potentially damaging and embarrassing for the government.
http://www.guardian.co.uk/Iraq/Story/0,2763,1155681,00.htmlBut in theory, there is no public interest defence:
The new Official Secrets Act replaces section two of the 1911 act, under which it was a criminal offence to disclose information without lawful authority.
The new act makes it an offence for any member, or former member, of the security services to disclose official information about their work. It is also an offence for a journalist to repeat any such disclosures.
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There will be no public interest defence, so an official would not be able to argue in court that they broke the law in the national interest.
The tightening of the law governing official secrets follows the Clive Ponting case in 1985.
http://news.bbc.co.uk/onthisday/hi/dates/stories/march/1/newsid_4251000/4251355.stmOn edit: perhaps it's timing that's important. Gun did her leak before the war started - so she could have said she was acting to prevent something. The present case, however, is about a leak after the other 'crime'. That, then would fall under 'public interest', rather than 'prevention of crime'.