NICOLA Sturgeon last night launched a cross-party appeal for the Chilcot Report into the conduct of the Iraq war to be made public ahead of the General Election.

The First Minister wrote to the leaders of all Holyrood parties asking them to present "a united stance in Scotland" and join her demand for the urgent release of the inquiry report. Its continued delay was "indefensible", she said.

Sir John Chilcot's inquiry into the run-up to the invasion of Iraq, the war and its aftermath was announced in 2009, and finished its hearings in February 2011.

The million-word report is believed to contain damning criticism of how then-Labour prime minister Tony Blair led the UK into the attack on Iraq alongside the US in 2003 on the false premise that Saddam Hussein had weapons of mass destruction.

The war saw the deaths of 179 UK service personnel and hundreds of thousands of Iraqi civilians, and many believe it ramped up Islamist terror around the world.

The Chilcot Inquiry asked to publish material covering 200 Cabinet-level discussions and 25 notes between Blair and then-US president George W Bush, but met fierce resistance from both the US and UK governments.

Although the report was finished last year, its publication is now being held up to allow those criticised in it to respond to its contents.

The UK Government has said that unless it receives the final report by the end of February, it will delay publication until after May's election. An alliance of the SNP, Plaid Cymru, the LibDems and a handful of Tory and Labour backbench MPs is pressing for swift publication, and has secured a Commons debate on the issue for January 29.

Plaid's Westminster leader, Elfyn Llywd, accused Labour and the Tories of a "stitch-up" to avoid mutual embarrassment before the election - the former because they advocated the invasion, the latter because they supported it.

Sturgeon is now trying to add the authority of the Holyrood parties to the publication demand.

In her letter to her fellow leaders, she said: "The war fundamentally undermined trust in the UK system of government, and publication of Chilcot in the earliest possible course is surely essential in order that lessons can be learned ... and responsibility allocated.

"I believe the delay to be a scandal, and that we as political leaders in Scotland should stand together and issue a joint call for the publication of Chilcot prior to the General Election in May, which at this stage seems a more than reasonable timescale."

The move heaps pressure on Blairite Scottish Labour leader Jim Murphy, who voted for the war.

Murphy last night said the report should be published "soon" but stopped short of demanding its release before the election.

He said: "There is rightly real public interest in the findings of such an important inquiry and I think it is right that there is the earliest possible publication of the report."

Scottish LibDem leader Willie Rennie said: "We agree with Nicola Sturgeon. It is important that the lessons from Chilcot are learned while there are people involved in Parliament who are in a position to answer for their actions.

"Liberal Democrats are pushing for the Chilcot report to be published within one week of receipt - even if it is submitted within the purdah period."

SNP Westminster leader Angus Robertson added: "The publication of the Chilcot report is all the more important now that Labour in Scotland is led by a Westminster MP who voted for the Iraq war."

Scottish Green MSP Patrick Harvie said he expected to respond "positively" to the letter, but a spokesman for Tory leader Ruth Davidson said: "The First Minister should concentrate on issues she has responsibility over like health, education and justice - that's what the Scottish people expect from her."