Shadow foreign secretary Hilary Benn has insisted he will not resign in protest at Jeremy Corbyn's opposition to bombing in Syria.

Mr Benn backs military action against Islamic State and suggested that Labour may end up agreeing to a free vote on the issue despite the party's leader's hopes for a "common view".

David Cameron has urged wavering Labour MPs to back military intervention in Syria, telling them to "vote on the basis of the arguments".

The Prime Minister said there was a "compelling" case for airstrikes and insisted MPs would allow the country to do the "right thing" if they supported them.

Speaking in Malta, where he is attending a Commonwealth summit, Mr Cameron said: "I believe there is a compelling case to take the effective action to keep our country safe."

Mr Corbyn is struggling to contain a shadow cabinet revolt after saying he could not support RAF action against IS.

The shadow cabinet will meet again on Monday, but it appeared that Mr Corbyn would face a rebellion from his top team if he tried to force them to oppose action.

Mr Benn told BBC Radio 4's Today programme: "I'm not going to resign because I am doing my job as shadow foreign secretary."

He added: "This is very complex, it is very difficult and each individual in the end will reach their own decision about what they think the right thing to do is.

"I respect those who take a different view, I genuinely do."

If Mr Benn refused to resign and then voted for military action against a whip imposed by Mr Corbyn, the leader would have little choice but to sack him.

Asked whether Mr Corbyn would be forced to allow a free vote on the issue, Mr Benn said: "That remains to be seen because the shadow cabinet will continue its discussions on Monday and it may be that that is where we end up."

Amid the growing crisis, Mr Corbyn has pulled out of a planned visit to campaign in the Oldham West by-election in order to deal with the situation.

There was anger among some Labour MPs after Mr Corbyn issued a letter following Thursday's shadow cabinet meeting saying the Prime Minister had failed to make a "convincing case" and that he could not support further military intervention.

The move was seen by some as an attempt to pre-empt next week's shadow cabinet meeting while appealing over the heads of MPs to the grass roots members who swept Mr Corbyn to the leadership.

Mr Benn said the leader was "perfectly entitled" to set out his view, although pointed out that members of the shadow cabinet had spent months wrestling with the issue and they were in the middle of reaching a decision.

Mr Corbyn is the "elected leader of the Labour Party with a very large mandate and he is perfectly entitled to express to Labour MPs his view and the conclusion he has reached about the choice it looks as though we are going to face in Parliament," Mr Benn said.

"Over the past two months, many of us in the shadow cabinet - Jeremy, myself, Diane Abbott, John McDonnell, Tom Watson, Charlie Falconer and others - have been wrestling with this question as to what the right thing to do is."

Shadow minister Emily Thornberry said there was a "brutally honest" debate within the party and accepted there would be a rebellion if a whip was imposed.

"I think that we have all agreed on a process and the process is that there was a shadow cabinet meeting yesterday, we are then to go back to our constituents and ask them what they think," she told Today.

"We have an open debate, and a brutally honest debate, going on within the Labour Party."

The shadow employment minister added: "We do usually act collectively, but I think on issues like this there are times when people cannot stick to a whip which is imposed."

The turmoil in Labour ranks complicates Mr Cameron's calculations on whether he has got the numbers to win a Commons vote on extending air strikes against IS - currently restricted to Iraq - into Syria.

The Prime Minister has repeatedly said he will not seek the support of the House unless he is certain of winning as defeat would hand a propaganda victory to the extremists.

But with some Conservative MPs still opposed to further military intervention, he is likely to need the support of a significant number of Labour MPs.

Mr Cameron said: "I thought many Members of Parliament on all sides of the House of Commons yesterday agreed there was a compelling case, so I would urge all of them to vote on the basis of the arguments for effective action on a compelling case to keep our country safe.

"Vote on those arguments and we can do the right thing."

Senior Labour MPs called for Mr Corbyn's resignation following the latest split.

Ex-minister John Spellar said Mr Corbyn's behaviour over the Syria vote had been "unacceptable".

He told BBC Radio 5 Live: "How does Jeremy Corbyn and his small group of tiny Trots in the bunker think they've got the unique view on it all?

"It's absolutely right for him to put that view in the shadow cabinet. It's right for them to discuss it.

"They thought they were going away to resume that discussion on Monday. He's now trying to pre-empt that and whip up a storm inside the party. It is, as I say, unacceptable."

He backed shadow cabinet members to stand their ground, suggesting that Mr Corbyn should fall on his sword instead: "Certainly, by the way, they should not resign. They should hold on to those places.

"If anyone should resign after this incident, it should be Jeremy Corbyn."

Another ex-minister, Fiona Mactaggart, said Mr Corbyn's leadership was "weak" and "unsustainable", although she was also unconvinced about the case for bombing Syria.

"He hasn't got a strategy to lead the party from where it is to where it needs to be and the people of the country can see that," the Slough MP told BBC Radio Berkshire.

"I think it probably is unsustainable. The problem is that my party - and bless it, I love it deeply - doesn't have the hunger for power that the Conservative Party has."

Asked if she thought Mr Corbyn should quit, she said: "I think that would be a sensible strategy because I think that the division at the moment is causing real problems."

Shadow chancellor Mr McDonnell, the most senior ally of Mr Corbyn in the shadow cabinet, appealed for calm and said the party was "working through the issues".

In a Twitter post he said: "On Syria, can everyone calm down. We're all simply working through the issues & coming to final decision.

"Don't mistake democracy for division."