Tony Blair received legal advice three months before the war on Iraq that military action would be unlawful without a second UN resolution, lawyers for Katharine Gun, the cleared whistleblower, have claimed.
Mrs Gun, who had secrecy charges against her dropped this week, was set to announce in court that Lord Goldsmith, the Attorney General, had changed his legal opinion opposing the war only last January. Mrs Gun would also have argued that her bosses at GCHQ had specifically advised her and other staff that war would be illegal without a further UN mandate.
Her assertions, which Mr Blair yesterday refused to deny, came as No 10 announced that the 1989 Official Secrets Act would be reviewed in the wake of the collapse of the Gun case.
The Attorney General also spoke for the first time on the affair, revealing that the decision to abandon the prosecution rested on new intelligence-based evidence received only this month.
He denied that the decision to drop the court action had anything to do with his own advice on the legality of war or had been motivated by political considerations.
Ms Gun's legal team had demanded disclosure of information on whether the Attorney General had been advising up to December 2002 that an attack without a second resolution would be illegal. Lord Goldsmith is alleged to have changed his position the following month to maintain that an invasion was legally justified.
Ms Gun, legally represented by the civil rights watchdog Liberty, stated that the management at GCHQ had sought to allay concern among staff that illegal bugging operations may have been carried out at the UN, and that these were designed to pave the way for an invasion of Iraq.
Legal documents passed to The Independent show Ms Gun's defence statement says "She honestly and reasonably believed (and had been informed by her employers) that the United Kingdom would not commit troops to military action in Iraq without a second UN resolution if to do so would be contrary to international law ..."
Ms Gun's lawyers were following up information that Lord Goldsmith had presented two versions of his legal opinion, successively hardening his stance about the legality of the war, to Downing Street in the weeks leading up to the war. The legal team was keen to pursue claims that he had changed his mind after being told by ministers that Saddam Hussein posed "an imminent threat" because of his alleged weapons of mass destruction. They wanted to know whether he was influenced by the information presented in government dossiers in September 2002 and February 2003 supposedly detailing the Iraqi arsenal, and claiming weapons with WMD warheads could be deployed within 45 minutes.
Mr Blair refused to be drawn on whether or when the Attorney General had changed his mind, saying: "[His] advice was clear. It was clear throughout and we acted upon it."
No 10 announced last night that a full review of the 1989 Official Secrets Act would take place to check whether the law should be amended in the light of the collapse of the Gun case.
Under sustained pressure from peers to explain why and when the charges had been dropped, Lord Goldsmith said "further material" had been received by the CPS "at the beginning of this month".
He was informed on 14 February of the new evidence and told Jack Straw, the Foreign Secretary, about it that same day. He informed Mr Straw once more about the progress of the case on Tuesday this week. He denied that Mr Straw had played a role in the decision to drop the case.
Lord Goldsmith said the CPS was obliged to consider "further material" gathered during the case and to "determine ... whether there is a realistic prospect of conviction".
WHEN IS A WAR LEGAL OR ILLEGAL?
MPs and international lawyers believe the decision to halt the prosecution of Katharine Gun is prima facie evidence that the Government's legal position is unsafe. They repeated their calls for the Attorney General to publish in full his advice on the legality of the war.
Sir Menzies Campbell, the Liberal Democrat foreign affairs spokesman, said there was little doubt Ms Gun's defence would have had "the legality of military action in Iraq" at its centre.
Among those who took issue with the government view of the legal case last year was the UN secretary general, Kofi Annan. He agreed with many members of the international legal community that United Nations resolution 1441 did not provide a case for war.
The resolution found Iraq to be in "material breach of its obligations under relevant [UN] resolutions". It gave Saddam a "final opportunity to comply". Failure would result in "serious consequences".