A parliamentary proposal to prosecute Tony Blair for "waging aggressive war against Iraq" has been backed by Scottish nationalists.

Independent MSP Margo MacDonald lodged a motion at the Scottish Parliament seeking "a simple amendment making illegal the waging of aggressive war with the intention of regime change so that Tony Blair could be brought to trial in Scotland".

It gained early support from SNP backbenchers Annabelle Ewing, Gordon MacDonald, John Finnie, Chic Brodie and Jim Eadie.

Ms MacDonald, a former SNP deputy leader, said Scotland has a unique opportunity to incorporate international criminal law into Scots law which is historically distinct.

Her husband Jim Sillars, another former SNP deputy leader, has called on "Alex Salmond's government or a bold backbencher" to "introduce retrospective legislation to indict the former prime minister on war crimes".

Writing in The Scotsman newspaper, he suggested an amendment to the International Criminal Court (Scotland) Act 2001 or a short Bill to import the ICC's definition of "aggression" into Scots law.

"We have to ask if it can ever be right that a leader who, through conspiracy with another power and who paved the way to aggressive war through lies, distortions and manipulation of a parliament and people, should go unpunished while the victims of that war are either lying destroyed in their many thousands, or are living with the terrible consequences of it?" he said.

"Blair knew aggressive war was a crime. He believed he was safe, there being no legal system that could touch him. There is one now - ours."

Mr Sillars remains an SNP member but retreated from frontline politics following a rift with Mr Salmond in the 1990s, while Ms MacDonald fell out of favour with the party in 2003 and was expelled after standing as an independent.