David Cameron has launched a fresh bid for British airstrikes in Syria in the wake of the devastating terror attacks in Paris.
In a statement to the House of Commons on Tuesday, the prime minister said Britain needed to attack ISIS in the Syrian city of Raqqa, which he branded the "head of the snake".
He announced he would respond to a critical report from the Commons home affairs committee who warned earlier this month that RAF strikes would simply be a "distraction" from the "key task to help end the suffering" in the war-torn country.
The prime minister's spokesperson said he would respond to each of the seven main concerns from the committee by the end of November. Number 10 will then determine whether Cameron has enough cross-party support from MPs before putting the motion to back airstrikes to a vote.
The BBC's Laura Kuenssberg reported that a meeting was already planned at the Ministry of Defence for the first week of December to go through the numbers.
I understand there's meeting at MOD to go through the potential numbers for a vote on airstrikes - briefings planned for 1st week December
But the PM's spokesman insisted that defence secretary Michael Fallon had been meeting MPs who had concerns about potential military action in Syria for the past few weeks.
The spokesman refused to be drawn on when a vote was likely to happen but insisted that the government had to be confident of winning a majority before putting the motion to the House.
He said a UN Security Council motion was not necessary for the air strike to take place. "I don't think we've got any questions on the legality. The Americans, the French are already taking part."
In his statement, Cameron said ISIS did not recognise or respect the border between Iraq, where Britain was conducting airstrikes, and Syria.
"It is in Syria, in Raqqa, that Isil has its headquarters and it is from Raqqa that some of the main threat against this country are planned and orchestrated," he said.
"Raqqa, if you like, is the head of the snake. Over Syria we are supporting our allies the US, France, Jordan and the Gulf countries with intelligence, with surveillance and with refuelling. But I believe, as I have said many times before, we should be doing more.
"We face a direct and growing threat to our country and we need to deal with it not just in Iraq but in Syria too."
Labour leader Jeremy Corbyn said his party was "ready to work" with the government to defeat ISIS, but said that military action must be backed by the United Nations.
Corbyn said military action wouldn't necessarily fix the situation, pointing to US president Barack Obama's comments earlier this year that ISIS was an "unintended consequence" of the Iraq invasion.
"That makes it essential that any military response that might be considered not only has consent but support of the international community and crucially, the legality from the United Nations," said the Labour leader.
"It is perfectly right to say that a few bombs and missiles won't transform the situation."