Tony Blair faced fresh questions about the legality of the war on Iraq last night after prosecutors dropped charges against a whistleblower who had threatened to expose secrets in court.
Katharine Gun, a former employee at GCHQ, the top-secret electronic eavesdropping centre, was charged with leaking secrets about preparations for the conflict but walked free from the Old Bailey when the case against her collapsed.
The Crown Prosecution Service triggered accusations of a cover-up when it refused to go into the reasons why, after nearly a year, it had decided to offer no evidence against Ms Gun.
Ms Gun said she was proud of her decision to leak the fact that the US had requested British help in "dirty tricks" against wavering members of the United Nations Security Council before the war.
Her lawyers suggested that the case had been dropped amid fears that Lord Goldsmith, the Attorney General, would have been forced to reveal details in court of his controversial legal opinion backing the conflict.
As well as the Attorney General, Jack Straw, the Foreign Secretary, and possibly Mr Blair himself might also have been forced to give evidence if the case had gone ahead.
Clare Short, a former cabinet minister, and opposition parties immediately called on the Prime Minister to publish Lord Goldsmith's advice in full to avoid allegations of a cover-up.
Talking about the collapse of the court case, Ms Short said that "there is something there that stinks".
She stressed that yesterday's events would fuel speculation that the Government's dossier on Iraq's weapons of mass destruction had been "hyped" specifically to help Lord Goldsmith prove that Saddam Hussein posed a threat under international law.
"This is enormously important. If they fiddled around to get legal authority and that involved exaggerating the intelligence then it wasn't just massaging public opinion, it was massaging legality," she said. "I believe there were shenanigans, to-ing and fro-ing and Blair would have been involved in that. There is something very fishy about it all. I think that stopping this case, while I'm glad for her [Ms Gun], that is probably what is behind this."
Ms Gun, 29, had been charged with breaching the Official Secrets Act after leaking a top-secret e-mail revealing US plans to bug delegates at the UN Security Council before a crucial vote on the conflict.
The formal decision not to continue the prosecution of the former GCHQ officer came within five hours of her legal team seeking disclosure of the legal advice given by the Attorney General, over the Iraq war. James Welch, the solicitor for the civil rights watchdog, Liberty, acting for Ms Gun, said: "Our case was that any advice the Government received on the legality of war was relevant to the case and we were prepared to go before a judge and argue for it to be disclosed.
"What Katharine would have said, had this case gone to trial, was that she honestly believed that the Government would not have gone to war if they thought going to war without a second resolution was unlawful. So, if that is the case, we wanted to know what the assessment was in government as to whether it would have been lawful or not."
The CPS refused to go into detail about why it had dropped the case but government sources said Lord Goldsmith had not been directly involved in the decision and it related purely to "evidential" matters. It was claimed by sources that a jury would simply have thrown the case out if it had gone to trial.
Downing Street refused to comment on the case. Mr Blair's official spokesman said: "This is a matter for the CPS."
Ben Emmerson QC, Ms Gun's counsel and one of the foremost human rights law specialists in the country, saidthere were precedents for governments having to disclose attorney generals' legal advice in court on Matrix Churchill, and a case involving Spanish fishing rights in British waters in the 1980s.
"Katharine Gunn is entitled to know and perhaps, more importantly, the public is entitled to know why, almost a year after her arrest, and three months after she was charged, the CPS has decided to drop the case," Mr Emmerson added.
Mark Ellison, for the Crown, said: "You will understand that consideration had been given to what is appropriate for the Crown to say. It is not appropriate to give further reasons.
"I am reluctant to go further than that unless the court requires I do."
Sir Menzies Campbell, the Liberal Democrat spokesman on foreign affairs, said: "The dropping of these charges will avoid severe government embarrassment. There is little doubt that Ms Gun, and her legal advisers, would have been bound to put the legality of military action in Iraq at the very centre of their defence. It is even possible that the full text of the Attorney General's advice to the Cabinet might have been published at last. This is a government retreat."