David Cameron has urged Tory MPs not to side with Jeremy Corbyn and "terrorist sympathisers" by opposing British air strikes against the Islamic State terror group in Syria.
The Prime Minister made the impassioned plea as he sought to bolster support ahead of tomorrow's crunch vote on escalating the UK's military involvement in the fight.
The Commons decks have been cleared for a 10 hour-plus debate on the case for deploying RAF jets against jihadist targets before a crunch vote at around 10pm.
Bombing missions are likely to begin within days if the House delivers what the Prime Minister hopes will be a comfortable majority in favour, thanks to the support of dozens of Labour MPs.
He called the vote after Mr Corbyn failed to win support for his anti-war stance in a shadow cabinet riven by bitter divides over the party's direction and granted Opposition MPs a free vote.
Up to 50 - including shadow foreign secretary Hilary Benn - are expected to back strikes despite a furious backlash from anti-war campaigners who mounted a noisy protest outside Parliament and Labour HQ.
Democratic Unionists and the Liberal Democrats are also backing air strikes, outweighing the voices of around a dozen Conservatives defying the party line to oppose action.
But critics of the policy - including the 54-strong Scottish National Party - have been emboldened by criticism of the PM's case from an influential committee and controversy over his claims about the numbers of moderate Syrian forces.
Mr Cameron set out his strategy as a direct response to a highly-critical assessment by the foreign affairs select committee but it voted by four to three that he "has not adequately addressed concerns" in key areas.
At least 110 MPs from six different parties have signed up to an amendment seeking to block air strikes - spearheaded by Tory FAC member John Baron and the SNP's Westminster leader Angus Robertson.
SNP foreign affairs spokesman Alex Salmond said he believed the Government was engaged in a desperate "dash to bombing" because it feared the tide of opinion was turning against it.
The majority would be "less than expected" he predicted - and did not entirely rule out a shock result if the lengthy debate swung wavering MPs against the PM's position.
Some have called for more details of the make-up of what Mr Cameron said in his case for strikes were 70,000 moderate opposition forces on the ground in Syria - amid concerns a significant number are extremists.
A Downing Street source said: "We will leave predictions to others.
"The PM believes there is a compelling case for action and we will make that case in the Commons."
Mr Corbyn insisted "more and more" Labour MPs were becoming sceptical about the proposals and said there was "no hiding place" for Labour MPs after he agreed to the free vote.
Any bombing would cause civilian casualties, he said.
"Is that actually going to help the political process or should we not be putting our efforts into a political settlement in Syria, supporting the Vienna process and what is going on with that? Surely that is a much more profitable way forward than this."
But prominent backbencher Dan Jarvis - who served multiple tours of Iraq and Afghanistan with the Parachute Regiment - invoked Labour leaders' support for joining the fight against Nazism in 1939 in declaring his support for air strikes.
"Labour has a tradition of standing for the national interest when our country is under threat," he wrote in the New Statesman magazine - challenging Mr Corbyn and other critics to present a credible alternative.
"When the War Cabinet met in 1939, it was ministers from our party - Clement Attlee and Arthur Greenwood - that tipped the balance in favour of resisting Nazism.
"Isil are the fascists of our time. Our struggle against them will be more complex, but the basic judgment it demands of us is the same: the readiness to do what is necessary to keep the British people safe."