Invade and be damned: Foreign Office lawyers say advice on legality of war was ignored

Tony Blair's most senior legal adviser will today be forced to explain why he ignored the advice from more experienced colleagues that the invasion of Iraq had no basis in law.

In its most explosive day of evidence to date, the Iraq inquiry heard that both Lord Goldsmith, the Attorney General who gave his legal backing to the invasion, and Jack Straw, Foreign Secretary at the time, brushed aside the unwelcome verdicts of leading international lawyers within the Foreign Office.

Sir Michael Wood, the department's chief legal adviser, revealed yesterday that he believed the March 2003 invasion was "contrary to international law". He said he considered resigning in the days before troops moved into Iraq after his deputy, Elizabeth Wilmshurst, left her post in protest. Declassified documents showed that he repeatedly warned Mr Straw that he believed military action to be unlawful. Sir Michael said that it was the "first and only occasion" in his 30 years at the Foreign Office that his legal advice had not been accepted. His evidence blew apart assertions made repeatedly by Mr Blair's ministers and advisers at the time of Ms Wilmshurst's resignation that her views were not shared by Sir Michael or other lawyers at the department.

"I considered that the use of force against Iraq in March 2003 was contrary to international law," Sir Michael told the inquiry. "In my opinion, that use of force had not been authorised by the [United Nations] Security Council, and had no other basis in international law."

Ms Wilmshurst, who was given a standing ovation after her evidence yesterday, said lawyers within the Foreign Office were "entirely of one view" that the invasion would need to be authorised by the UN to be lawful, while the prospect of committing troops without the UN's explicit approval was treated as a "nightmare scenario". She said Mr Blair's team had treated legal clearance for launching the invasion as "simply an impediment that had to be got over before the policy could be implemented".

Mr Straw's role in dismissing legal concerns about the use of force will also come under the spotlight when he returns to the inquiry next month, after it emerged that he overruled advice from both Sir Michael and Lord Goldsmith. Sir Michael wrote several notes to Mr Straw to clarify that he believed the use of military action against Saddam Hussein to be unlawful without UN clearance. In one, Sir Michael stated: "To advocate the use of force without a proper legal basis is to advocate the commission of the crime of aggression, one of the most serious offences under international law."

In a letter to Mr Straw on 24 January 2003, two months before the war, Sir Michael warned him: "I hope that there's no doubt in anyone's mind that without a further decision of the council... the United Kingdom cannot lawfully use force against Iraq." He told the inquiry that he had written the note because Mr Straw's views were "so completely wrong from a legal point of view". He added that lawyers within the Foreign Office believed it was "pretty straightforward" that there was no legal basis for an invasion. However, Mr Straw fired a memo back, saying he did not accept Sir Michael's legal judgment, adding that international law was an "uncertain field".

An early draft of Lord Goldsmith's legal advice on the Iraq invasion issued in January 2003, which suggested that only the UN could authorise the use of force against Saddam, provoked a similarly scathing response from Mr Straw. He told the Attorney General that his judgment ignored "both the negotiating history and the wording" of previous UN resolutions. His missives emerged just a week after he told the inquiry that he had warned Mr Blair about the legal problems of an invasion.

Secret documents, published for the first time yesterday, also revealed that Lord Goldsmith told No 10 that he had continuing doubts over the war's legality without explicit permission from the UN. Resolution 1441, agreed in November 2002 and designed to put further pressure on Iraq, was used by Mr Blair and the Bush administration as the legal basis for the invasion. But declassified documents showed that Lord Goldsmith told Mr Blair's team he was "pessimistic" that resolution 1441 could legally justify Saddam's removal.

Lord Goldsmith made the comments in a telephone call with Jonathan Powell, Mr Blair's chief of staff. He said that he had heard "Chinese whispers" that No 10 was planning to use a breach of the resolution as the legal basis for military action. During the call, Mr Powell admitted that Mr Blair was "under no illusion as to the attorney's views on the issue". However, just days before the invasion took place, Lord Goldsmith concluded that resolution 1441 did give legal cover for the invasion after being asked by Mr Blair to make a final ruling.

Ms Wilmshurst said it was "extraordinary" that Lord Goldsmith's final advice had been sought so late on, when troops had already gathered around Iraq in preparation for the invasion. "The process followed was lamentable," she said, adding that blocking military action at the last minute would have given Saddam a "massive PR advantage".

"We were talking about the massive invasion of another country, the change in the government and the occupation of the country, and in those circumstances it did seem to me that we should follow the safest route," she said. "It was clear that the Attorney General was not going to stand in the way of the Government."

Today, Lord Goldsmith is expected to reject claims that Mr Blair's allies forced him to change his mind about the legality of the war. He is said to be frustrated by the suggestion that his professional opinion was influenced by political pressure. "He has always been a lawyer first," a friend said last night.

Profile: Elizabeth Wilmshurst

Two days before tanks rolled into Iraq in March 2003, Elizabeth Wilmshurst wrote the letter that brought her 29-year Whitehall career to an end. She joined the Foreign Office in 1974 as an assistant legal counsel after a brief spell as a law lecturer. She rose smoothly through the civil service ranks, taking in postings to the Attorney-General's Office and to the UK mission at the United Nations in New York. In 1999 Ms Wilmshurst returned to the Foreign Office as No 2 in its legal department. As the Iraq crisis blew up, her reservations over the war's legality – which were apparently shared by all of her colleagues – intensified to the point where she concluded she could not stay in her job. In her letter, she told her boss, Sir Michael Wood, that she could not "in conscience" remain. She requested early retirement (even though she was only 54) and, failing that, said she wanted to resign. Previously unknown outside legal circles, she was hailed as a brave whistleblower by anti-war campaigners. Ministers responded by portraying her as a maverick. Today Ms Wilmshurst is a visiting professor at University College London and a specialist in international law at the Chatham House think-tank.

Profile: Sir Michael Wood

Sir Michael, who spent three years with the UK mission to the UN and is an expert in Security Council law, shared his deputy's doubts over the legality of the Iraq war. The career civil servant disclosed yesterday he considered resigning on the eve of the invasion but decided to stay on. He was knighted the next year and retired in 2006. Sir Michael, 62, is now on the UN international law commission and a senior fellow in the law faculty at Cambridge University.