Goldsmith will advise that war on Iraq is legal

Lord Goldsmith, the Attorney General, will advise Parliament today that an attack on Iraq is justified under international law without a second United Nations resolution.

The Government's senior legal adviser will bolster Britain's case for war by telling Parliament that UN resolution 1441 and previous UN resolutions allow for a military strike.

His public intervention will be interpreted as a sign that the momentum for war is growing and of ministers' frustration at the chances of a second resolution being passed by the UN Security Council.

Lord Goldsmith, whose advice to the Government is usually private, will tell the House of Lords that 1441 warns of "serious consequences" if Saddam Hussein does not comply.

Lord Goldsmith is believed to have told Tony Blair last week that the legal case for war could be weakened if a second resolution was vetoed or voted down by a majority of the Security Council. The latest advice is expected to prove controversial. Last week Kofi Annan, the UN secretary general, warned that military action would be outside the organisation's charter.

Lord Goodhart, a senior QC and frontbench Liberal Democrat peer, said that most lawyers disagreed with the Attorney General. "Lord Goldsmith would at best be authorising the mobilisation of troops on the basis of a highly questionable statement of the law," he said.

But cabinet ministers lined up yesterday to insist that international law already justified a strike against President Saddam. Gordon Brown, the Chancellor of the Exchequer, said: "The Government would not be acting in the way it has done without there being a legal basis for its actions."

He said on BBC1's Breakfast with Frost that resolution 1441 referred to "serious consequences" if Saddam failed to comply. He also pointed to resolution 678, which said the international community could use all necessary means to uphold security.

Alan Milburn, the Health Secretary, said: "In resolution 1441, what the United Nations said unanimously – including the French government – was that this was one final opportunity for Saddam Hussein to comply with his international obligations. It threatened him with serious consequences if he failed to comply with those obligations. Now he has a final opportunity to do so."

Jack Straw, the Foreign Secretary, rejected claims that British troops could find themselves facing charges under international law for attacking Iraq illegally. "The legality of any military action will be fully supported by international law. It would be completely improper were that not the case," he said.

Jose Maria Aznar, the Spanish Prime Minister, said that although "a further resolution would be politically desirable ... from a legal point of view it is not indispensable".