A former deputy leader of the SNP has launched a bid to have Prime Minister Tony Blair prosecuted in Scotland for his decision to go to war in Iraq.

Jim Sillars, the former MP for Govan, alleges Mr Blair "waged aggressive war" against the Middle East country and can be charged under Scots law.

Mr Sillars submitted a 24-page document supporting his case to Elish Angiolini, the Lord Advocate, on Friday and yesterday said he was confident that the Prime Minister would eventually stand trial in Scotland.

However, a leading expert on international law said it was highly unlikely that Mr Sillars's attempts to have Mr Blair prosecuted would succeed.

Speaking at the Scottish Parliament alongside his wife, the Lothians MSP Margo MacDonald, Mr Sillars said Scotland was now the only place in the world where the Prime Minister could face legal action over Iraq.

He said: "There is overwhelming evidence that Blair is guilty of a conspiracy to wage aggressive war and of waging aggressive war.

"There can be no prosecution at the international criminal court because it doesn't have jurisdiction, there is no chance of a special court being convened by the United Nations because Britain and the US have a veto and no chance of a prosecution in England and Wales.

"But Scots law is an entirely different entity and entirely different jurisdiction with different rules and procedures."

Mr Sillars said the High Court of Justiciary has powers to declare new ways of committing existing crimes, namely waging aggressive war on another country.

He argued those so-called "declaratory powers" would therefore allow Ms Angiolini to bring a case against the Prime Minister.

Alongside his legal document, Mr Sillars has also submitted a range of documents taken from the internet which he claims prove that Mr Blair took part in a conspiracy in order to justify the military campaign in Iraq.

These include cabinet memos, the memoirs of the former weapons inspector Hans Blix, excerpts from the Butler report into the war and other pieces of research from both sides of the Atlantic.

Mr Sillars said that, taken together, the evidence he has gathered since beginning his investigations in January provide a compelling case for the Prime Minister's prosecution.

"The Lord Advocate would have to give a very good explanation to say why, with the evidence presented to her, she didn't proceed with an investigation," he said.

"This is a serious document about a very serious matter."

Mr Sillars said demonstrating no-one was above the law would lend moral authority to the West's battle against international terrorism.

He added: "It's the morality of our position that will ultimately determine whether we win that struggle or not."

However, John Grant, a former professor at Glasgow University's law school and now a professor at Lewis & Clark law school in Portland, Oregon, last night said he was not convinced that Mr Sillars's attempts to have Tony Blair stand trial will be successful.

He said: "The Scottish declaratory power, while used relatively recently in minor areas, has been seen by some as contrary to European human rights law, which requires that crimes should be known in advance of the acts that constitute them and not legislated by courts."

A spokesman for the Crown Office said: "We can confirm receipt of correspondence from Jim Sillars. A response will be issued in due course."

A Downing Street spokesman said: "The government has always acted in accordance with international law."