Foreign Office lawyers have formally advised Jack Straw that it would be illegal under international law for Britain to support any US-led military action against Iran.

The advice given to the Foreign Secretary in the last few weeks is thought to have prompted his open criticism last week of Tony Blair’s backing for President George Bush, who has refused to rule out military action against the regime of President Mahmoud Ahmadinejad.

In the run-up to the Iraq invasion in 2003, Straw received similar private advice from senior Foreign Office lawyers who had also advised the attorney general, Lord Goldsmith, on the illegality of an invasion without the express authority of the United Nations Security Council.

The Foreign Office’s deputy legal adviser, Elizabeth Wilmshurst, later resigned when the attorney general reversed his initial view on the war’s legality.

Sources within the Foreign Office say there is an express desire that this time their legal advice is heard and acted upon.

A source close to Straw told the Sunday Herald: “There is now a clear paper trail of legal advice.�?

Straw last week passed on the legal advice to some of his cabinet colleagues after Blair effectively backed the White House view that military action could not be ruled out.

Although the Prime Minister claimed any other option would be a “message of weakness�? Straw said it would be “inconceivable�?that Britain would support a military strike against Tehran.

The Foreign Office’s lawyers have gone further than merely advising on the legality of military assistance. It is thought their advice stretched to the use of British military advisers, UK airspace and even the dangers of Tony Blair expressing support which could be taken as legitimising a US-led attack without the express authority of the United Nations.

The lawyers have urged the British government to await the full report on Iran by the International Atomic Energy Authority’s head, Mohamed ElBaradei. His report will be handed to the Security Council in New York this week.

The report is not expected to identify a “smoking gun�?that would point to Iran seeking to weaponise a nuclear programme that it still claims is for peaceful civilian energy generation. The matter will then effectively go back to the Security Council to consider what to do next.

But the White House is concerned that a rogue state is being given too much time by the UN, as it believes it did with Iraq. A State Department official said last week that time was running out for Iran and if the UN did not take action over a state which it claimed “was violating every nuclear agreement it has ever made�?then it was time “for other countries to use their leverage�?

To add to the pressure on Blair not to become entangled in any military action against Iran, the officer in charge of army recruitment in Scotland has warned that the shortage of troops is so severe that another overseas conflict �?or a resurgence of domestic terrorism in Northern Ireland �?would lead to the UK having to pull troops out of Iraq or Afghanistan.

In an interview with the Sunday Herald, Lieutenant Colonel David Steele warned that although the UK armed forces can currently cope with its domestic and overseas duties, any additional strain would be too much.

“We are stretched,�?he said, “but at the moment we have enough men to adequately do the job. If there was one more operation, we would have to look at it very carefully and ask ourselves if we could do the job.

“If the Northern Ireland situation worsened suddenly then we’d have to examine all our commitments.

“We are heavily committed at the moment. If there was another overseas conflict, we’d have to analyse the situation and see if we could commit to it or not. If it was something that we really had to do, then we might have to stop doing something else [in another theatre of conflict].�?

Recruitment into the Scottish battalions �?recently amalgamated in the Royal Regiment of Scotland �?has fallen between 10% and 15% over the years since the war on terror and the war in Iraq broke out.

In the year 2000, some 1300 soldiers joined Scottish regiments each year. Today, only 1100 are joining.

The Scottish battalions will tomorrow launch a huge recruiting campaign across the county. This week, recruiting sergeants will be targeting deprived areas such as Clydebank in the hope of getting young disadvantaged men to sign up. Army recruiters and regimental pipers will be in Clydebank Shopping Centre tomorrow, aiming to attract unemployed youths with the promise of a career and travel.

Copyright © 2006 newsquest (sunday herald) limited