Shadow Chancellor John McDonnell has called for a free vote on air strikes in Syria as the issue is "above party politics". McDonnell is the latest ally of Jeremy Corbyn to contribute to the divisive issue which has threatened to split the higher echelons of the Labour party.

The MP for Hayes and Harlington, Middlesex, believes that MPs should be able to follow their "own judgement" on the decision to allow air strikes over the worn-torn nation. On Thursday, 26 November, Corbyn wrote a letter to Labour MPs saying that he could not support air strikes against Islamic State (Isis) extremists in Syria.

But Hilary Benn, the party's shadow foreign secretary, argued that there was a "compelling" case for British air strikes on IS targets inside Syria. Labour's Deputy Leader Tom Watson has supported Benn's position saying that there is an "imminent security threat" to the UK.

To add to the discontent Fiona Mactaggart MP said that "weak leadership" was causing damaging divisions within the party. In 2014, Mactaggart did not vote when the government approved military action against IS forces in Iraq.

Also, Labour veteran and Work and Pensions Committee chair Frank Field stepped forward to declare that Jeremy Corbyn should resign, saying Labour "needs an alternative leader".

Other shadow cabinet members are also said to have been swayed by David Cameron's speech to parliament on Thursday, when he declared: "We must tackle Isis in Syria, as we are doing in neighbouring Iraq, in order to deal with the threat that Isis poses to the region and to our security here at home."

Vote by conscience

A commons vote is expected to be held on the issue. McDonnell, speaking on BBC Radio 4's Any Questions, said he believes Corbyn should allow a free vote: "There are some issues like going to war that should be above party politics, and I think we are moving to a situation where hopefully in all parties on issues like this a moral conscience should be above the whip as well.

"On certain issues, the ones really above party politics, we have got to have mature politics in our democracy now. This is a matter of conscience. You are sending people out possibly to die.

"There shouldn't be any party discipline on matters like this. You should follow your own judgement on what you think is best for the constituency and the country."

Although the UK is already bombing targets in Iraq, McDonnell said that he opposes any air strikes in Syria. McDonnell added that a "horrendous mistake" of the 2003 Iraq War was that many MPs were "whipped" into making decisions that did not believe in.

McDonnell voted 'no' in the September 2014, authorising air strikes in Iraq. Field and Benn both voted in favour of the strikes. However, according to Hansard's records Watson and Mactaggart, a member of parliament's Intelligence and Security Committee at the time, abstained. Labour MPs had been instructed to attend the vote through a three-line whip.

Corbyn has sent out a survey to party members asking for their views amidst rumours of resignations from the shadow cabinet. But his deputy, Tom Watson, has said he will not consider resigning.

In the past few days, French president François Hollande has also called on British MPs to support air strikes whilst speaking at the Commonwealth Heads of Government Meeting in Malta. He said: "I do hope that the House of Commons will be able to meet the request of Prime Minister Cameron."