Labour leader Jeremy Corbyn
The pro-Jeremy Corbyn group Momentum spoke to IBTimes UK about their lobbying plans Getty Images

Labour pressure group Momentum has claimed it has "overwhelming support" from its supporters to launch an anti-intervention campaign and back Jeremy Corbyn amid a party row over UK air strikes on Syria. But the left-wing organisation told IBTimes UKit has not balloted its supporters on the issue.

James Schneider, a spokesman for the group, said: "Momentum arises out of Corbyn's leadership campaign, which decisively won the biggest mandate in any Labour leadership election on the basis of three pillars – a new politics, a new economics and a new relationship with the world.

"It's on the basis of that third pillar that we have put out our call to our supporters and others to ask their MPs to vote against bombing Syria.

"We are still setting up our full governance structures which will enable us to democratically decide our direction. But in many of the groups which have been set up, it is the overwhelming consensus that [David Cameron] has not made the case for bombing Syria."

The comments come after Momentum wrote to its supporters and asked them to lobby their MPs over possible air strikes by the UK on Syria. The anti-interventionist call followed Corbyn's letter to Labour MPs, which explained that the former Stop the War Coalition chair would not back British military intervention against Islamic State (Isis) in Syria.

"The prime minister did not set out a coherent strategy, coordinated through the UN, for the defeat of Isis. Nor has he been able to explain what a credible and acceptable ground force could retake and hold territory freed from Isis control by an intensified air campaign," the Labour leader wrote.

The letter triggered a row at the top of Labour as shadow foreign secretary Hilary Benn argued there was a "compelling" case for UK air strikes on Syria. Corbyn has also faced opposition among his own ranks after he hinted he would not give Labour MPs a free vote on the issue.

The row comes ahead of a shadow cabinet meeting on 30 November, where Labour's top team is expected to debate the issue, and ahead of the Oldham West and Royton by-election on 3 December.

Jim McMahon is the bookies' favourite to win back the Greater Manchester seat for Labour over Ukip's John Bickley and Momentum told IBTimes UK it expects to send "five coach loads" of activists to campaign for the Oldham Council leader.

Meanwhile, the most recent opinion poll from YouGov showed the public backs Prime Minister David Cameron's call to bomb Syria. The survey, of more than 1,600 voters between 23 and 24 November, found 59% of people supported such an intervention and only 20% of respondents disapproved of it.