A moral precedent, but not a legal one

Katharine Gun, the GCHQ translator, was charged under Section 1 of the Official Secrets Act 1989 and faceda possible two years in jail if found guilty.

Section 1 states that it is an offence for a member or ex-member of the security and intelligence services to disclose information obtained through their official position without authority. Since 1997 five people have been found guilty of breaching the Act. Ms Gun broke the law after admitting to supplying the Observer newspaper with an e-mail from America's National Security Agency to GCHQ in Cheltenham.

But the CPS decision not to press charges - which followed advice given by the Attorney General Lord Goldsmith, who has to authorise a prosecution under the Act - meant that the case never came to trial. James Welch, a director of the human rights group Liberty and Ms Gun's solicitor, said yesterday: "I don't think this case has any legal consequences. It does not set a legal precedent, but it might set a moral one."

Ms Gun's legal team had intended to argue that she had acted out of necessity and felt morally compelled to avoid death or injury to others. If the prosecution had challenged the legality of the defence, which was likely, Liberty could have gone to the Court of Appeal.