A decision to bomb Islamic State terrorists in Syria will "almost inevitably lead to the deaths of innocents", Jeremy Corbyn has said.

The leader of the opposition told MPs they faced a "most serious, solemn and morally challenging" decision as they debated expanding UK military involvement in the country.

"It is one with potentially far reaching consequences for us all here in Britain as well as the people of Syria and the wider Middle East," he said.

"For all members to take a decision that will put British servicemen and women in harms way and almost inevitably lead to the deaths of innocents is a heavy responsibility.

"It must be treated with the utmost seriousness and respect given to those who make a different judgement about the right course of action to take."

Mr Corbyn also called on the Prime Minister to apologise for remarks attributed to him.

"To brand those who plan to vote against the Government as 'terrorist sympathisers' both demeans the office of the Prime Minister and I believe undermines the seriousness of deliberations we are having today," he said.

"If the Prime Minister now wants to apologise for those remarks I'd be happy to give way to him to do so."

Mr Corbyn then paused but Mr Cameron did not rise to speak.

Mr Corbyn refused to answer directly whether he would want Britain to also withdraw from air strikes against IS in Iraq, a reaction which prompted howls of protest from MPs.

The Labour leader was one of the relatively few MPs to vote against that action and he was asked by pro-war Labour colleague John Woodcock whether he wants to remove air protection for Kurdish forces in Iraq.

The Labour MP for Barrow and Furness asked: "Could you be clear at this Despatch Box that you or anyone on this bench in no way will want to remove the air protection which was voted on with an overwhelming majority in the House 14 months ago?"

Mr Corbyn replied: "It is not part of the motion today so we move on with this debate."

Mr Corbyn accused the Prime Minster of attempting to rush a vote through the Commons before public opinion shifts against "ill-thought-out" military action.

A YouGov poll for the Times showed the proportion of Britons supporting air strikes has dropped from 59% to 48% and the Labour leader said people were realising that Mr Cameron's plan "does not stack up".

Mr Corbyn said: "It's impossible, I think, to avoid the conclusion that the Prime Minister understands that public opinion is moving increasingly against what I believe to be an ill- thought-out rush to war.

"And he wants to hold this vote before the opinion grows even further against it.

"Whether it's a lack of strategy worth the name, the absence of credible ground troops, the missing diplomatic plan for a Syrian settlement, the failure to address the impact of the terrorist threat, or the refugee crisis and civilian casualties, it's becoming increasingly clear that the Prime Minister's proposals for military action simply do not stack up."

Mr Corbyn highlighted the "scarcely surprising" Foreign Affairs Committee's rejection of the case for military action, insisting: "In other words, the committee judged that the Prime Minister's case for bombing had failed its tests."

But he was criticised by committee chair Crispin Blunt for a "weak point" which did not take into account the absence of Labour MPs Mike Gapes and Ann Clwyd from its vote last night, insisting they would have tipped the balance in favour of action.

Intervening, the Tory MP said: "That the committee resolved four to three that the Prime Minister has not adequately addressed conceders contained in the committee's second report, with the absence of Mr Gapes and Ms Clwyd, who would have resisted that motion.

"But it is on a narrow point where logically it is almost impossible for the Prime Minister to adequately meet those concerns given the fact that he is not in a position to produce sufficient detail obviously to satisfy some of my colleagues.

"It is a very weak point for you to rely on."

Mr Corbyn warned of "mission creep" and the "real possibility" of British troops being sent to Syria should MPs support the extension of air strikes.

He said: "The logic of an extended air campaign is in fact mission creep, and Western boots on the ground - whatever the Prime Minister may say now about keeping British combat troops out of the way - are a real possibility."

He added that the UN Security Council resolution does not give "clear and unambiguous authorisation" for UK bombing in Syria.

Mr Corbyn also said there is a "clear risk of potentially disastrous incidents", adding that the shooting down of a Russian military aircraft by Turkish forces is a "sign of the danger of a serious escalation of this whole issue".

Addressing the impact of air strikes in Syria on security in Britain, Mr Corbyn said: "It is critically important that we are honest with the British people about the potential consequences of the action the Prime Minister is proposing today.

"I'm aware that there are those with military experience, including members on the benches opposite as well as this side, who have argued that extending UK bombing will - and I quote - 'increase the short-term risks of terrorist attacks in Britain'.

"We should also remember the impact on communities here in Britain. Sadly, since the Paris attacks there has been a sharp increase in Islamophobic incidents and physical attacks."

He added: "The message from all of us must go out: none of us - and we can say this together - will tolerate any form of anti-Semitism, Islamophobia or racism in this country."

Mr Corbyn said one of his Islington North constituents who is Syrian, Abdulaziz Almashi, asked if the Prime Minister could guarantee the safety of his family who live in IS-controlled territory.