ALEX Salmond has been criticised unfairly, Nicola Sturgeon has insisted, after he missed a key Commons debate on Syria to attend a portrait unveiling.

Ms Sturgeon insisted there had been a “mischaracterisation” of the MP for Gordon’s position after he failed to attend Thursday's statement setting out the Government's position to unveil Gerard Burns's painting of himself at the Scottish National Galleries in Edinburgh.

The First Minister said the SNP foreign affairs spokesman would attend the Commons debate and vote on extending airstrikes to Syria when it takes place.

She explained: “Alec is a member of the Scottish Parliament. He was attending the Scottish Parliament. He was doing other things, including an event in the Scottish Parliament that had been planned for veterans; so he was discharging his responsibilities as an MSP.”

Mr Salmond, 60, is still the MSP for Aberdeenshire East.

The First Minister went on: “As he said himself he had had an intelligence briefing on privy counsel terms in London the night before(David Cameron’s Commons statement), so he was well-briefed and Angus Robertson, as leader of the Westminster Group, it was always his responsibility to respond to the PM.”

She stressed: “When the vote happens, if it does happen in the House of Commons, and there is a debate, Alec will take part in that debate.”

Ms Sturgeon added: “The criticism of him was deeply unfair.”

Mr Salmond’s political opponents focused on the event at the Scottish National Portrait Gallery, where the former FM and party leader unveiled the likeness created by the award-winning painter Gerard Burns.

Ruth Davidson, the Scottish Conservative leader, said: "The fact the SNP's foreign affairs spokesman would apparently prefer to unveil a portrait of himself in Edinburgh than take his seat in the Commons during the Prime Minister's statement on UK actions in Syria speaks volumes.

"Alex Salmond has form in unveiling vanity projects to himself but he needs to remember he's paid - twice over - to be a parliamentarian, not an art critic."

Willie Rennie, the Scottish Liberal Democrat leader, said: "Nothing gets in the way of Alex Salmond's ego including debating war and peace in our country and the Middle East.

"His absence from the Commons at this critical moment means we will be more sceptical about his motivations the next time he expresses outrage on the matter."

A Scottish Labour spokesman said: "If Alex Salmond was chocolate he would eat himself. On the day that he had a job to do in Parliament over Syria it's ridiculous that the SNP's foreign affairs spokesperson was in Edinburgh to look at a picture of himself."

The SNP dismissed the criticism as "crass and ridiculous".

Mr Salmond defended his decision by saying that the Commons statement was given by the Prime Minister and “therefore, it is responded to by the leader of the party. That's the way it should be".