By John Knox BBC Scotland political reporter

Tony Blair has received endorsement for his stance on Iraq from a majority of MSPs at Holyrood.

The Scottish National Party had hoped to embarrass the prime minister by winning a debate at Holyrood over a matter which is, strictly, reserved to Westminster.

In the event, the SNP motion was defeated by 16 votes.

The Labour Party closed ranks and its MSPs were joined by the Tories in supporting the UK Government's line that Saddam Hussein must get rid of his weapons of mass destruction or face invasion.

They are using a tense and worrying international situation to illuminate their views on the constitution Tom McCabe, Labour MSP

As if to emphasise the point, the aircraft carrier Ark Royal steamed out of the Clyde on Thursday and off to the Gulf to take part in the military build-up.

The prime minister was in Scotland for talks with the police in Edinburgh on gun crime and for a party event in Stirling.

After hearing the Holyrood result, Mr Blair said he was glad that the Scottish Labour Party was backing his position.

But he repeated his view that Saddam Hussein had only to fail to hand over his weapons of mass destruction to trigger a second United Nations resolution.

And he said Britain and the United States would not allow action against Iraq to be blocked by one country voting against it.

Real evidence

SNP leader John Swinney told MSPs: "The US and UK governments are pursuing an inevitable path to war and I believe it is our duty to steer this government away from this inappropriate approach

"Threatening to take unilateral action does not uphold the UN's authority, it helps to destroy it and we as a parliament should have none of it."

The SNP is insisting that no military action should take place unless the UN inspectors find real evidence of chemical, biological or nuclear weapons in Iraq and unless there is a fresh UN mandate for war.

Mr Swinney argued that Westminster had not properly debated the issue of war with Iraq and that the Scottish Parliament had every right to do so, even though foreign affairs and defence are not devolved matters.

He said: "It is not just this parliament's right, it is this parliament's duty to reflect Scotland's long and honourable history of internationalism."

Labour's Tom McCabe accused the SNP of being "opportunistic and repugnant".

War is being prepared for regardless of whether weapons of mass destruction are discovered or not Tommy Sheridan, Socialist MSP

He said: "They are using a tense and worrying international situation to illuminate their views on the constitution at a time when brave young women and men in our armed forces may find themselves in deadly conflict."

The Conservatives backed the Labour amendment. Phil Gallie said the country had to trust the prime minister of the day.

The Liberal Democrats - despite being in coalition with Labour in the Scottish Executive - supported the SNP call for a second UN resolution.

Tavish Scott said the UN weapons inspectors in Iraq should be given the time to finish their work.

He said: "The United States now has a policy of taking pre-emptive action against any state which threatens world peace. That strikes me as being profoundly dangerous."

A final amendment was moved by Tommy Sheridan for the Scottish Socialist Party.

One-resolution policy

He said there is no moral, humanitarian or military reason to go to war with Iraq and he called for a campaign of civil disobedience against it.

"War is being prepared for regardless of whether weapons of mass destruction are discovered or not.

"The reason North Korea is being treated differently from Iraq is because North Korea does not have oil."

The Green MSP Robin Harper and the Labour rebel John McAllion signed Tommy Sheridan's amendment.

As the debate proceeded it was clear there would be no overt rebellion by Labour backbenchers, though many are known to harbour serious doubts about Tony Blair's one-resolution policy.

Mr Sheridan's all-out anti-war amendment was defeated by 112 votes to six with three abstentions

When the series of votes was taken at 1700 GMT, the SNP motion was defeated by 67 votes to 51 with three abstentions.

Labour and the Conservatives voted together and the Liberal Democrats voted with the SNP.

The three abstainers were all Labour backbenchers, Gordon Jackson, Pauline McNeill and Elaine Smith.

Mr Sheridan's all-out anti-war amendment was defeated by 112 votes to six with three abstentions.

It had been the best parliamentary debate of the year so far. The irony was that it was on a subject over which Holyrood has no direct control.

But then perhaps talking shops serve a useful purpose after all.