LABOUR’S parliamentary party is at war with leader Jeremy Corbyn again, over an SNP motion accusing Tony Blair of lying in the run up to the war in Iraq.

At a meeting on Monday night, Corbyn’s backbenchers took the unusual step of instructing the leadership to impose a three-line whip, making it mandatory for all Labour MPs to vote against the SNP motion.

This was, in part, retaliation for the suggestion “senior figures” in Labour could vote with the SNP.

However, Corbyn declined, insisting it be a one-line whip and Labour MPs be allowed to vote how they want or to not vote at all, setting the party on course for yet another civil war.

It came as the latest ICM poll suggested the Tories, themselves in a difficult place because of the Brexit splits, had pulled even further ahead of Labour.

Taken after the Autumn Statement, the Tories were up two points on 44 per cent, 16 points ahead of Labour on 28 per cent, and Ukip on 12 per cent. The Liberal Democrats were on seven per cent and the Greens on one.

The motion says that the Chilcot Inquiry “provided substantial evidence of misleading information presented by the then Prime Minister and others on the development of the then Government’s policy towards the invasion of Iraq as shown most clearly in the contrast between private correspondence to the United States Government and public statements to Parliament and people”.

Specifically, the release of Blair’s “I’ll be with you whatever” note is proof, the SNP say, that the former Prime Minister had knowingly lied to Parliament.

If passed, it would force a parliamentary inquiry into Blair’s conduct, with the possibility of him being stripped of his Privy Council membership, an honour granted to senior ministers.

According to the Huffington Post, former ministers Ben Bradshaw and Pat McFadden were furious at the suggestion the Labour Party would not robustly defend Blair’s honour.

Bradshaw reportedly said the SNP motion “deliberately distorted” the findings of the Chilcot report and “perpetuates the lie” that Tony Blair misled Parliament and cabinet “when Chilcot made clear he acted in good faith”.

McFadden said the “mendacious motion” traduced a leader who led Labour to three consecutive election victories, and attacked Corbyn for his praise of Fidel Castro.