Tony Blair has demanded Britain and the United States intervene in the Syrian civil war, warning that the regime of Bashar al-Assad is launching an attack on civilians on a scale "not seen since the dark days of Saddam".
The former prime minister who led Britain to war in Iraq an Afghanistan said it was "time we took a side". Writing in The Times on Tuesday, Blair said: "People wince at the thought of intervention. But contemplate the future consequence of inaction and shudder."
He said: "Western policy is at a crossroads: commentary or action; shaping events or reacting to them. After the long and painful campaigns in Iraq and Afghanistan, I understand every impulse to stay clear of the turmoil, to watch but not to intervene, to ratchet up language but not to engage in the hard, even harsh business of changing reality on the ground. But we have collectively to understand the consequences of wringing our hands instead of putting them to work."
In an apparent reference to Russian support for the regime, he added: "Others are taking sides. They’re not terrified of the prospect of intervention. They’re intervening. To support an assault on civilians not seen since the dark days of Saddam."
President Obama and David Cameron have raised expectations that the West is preparing to take military action against Assad - having accused him of using chemical weapons.
But there is nervousness in Westminster that the British government may take part in an air campaign before it is sanctioned by parliament - which does not return from summer recess until Monday. Cameron will decide today whether or not to recall MPs to the Commons early, potentially as soon as Wednesday.
The Labour Party has demanded that MPs be given a chance to voice their opinion on any military intervention. Ed Miliband has not yet set out a clear view on whether he would support air strikes.
A substantial number of Conservative MPs are opposed to intervening in the conflict and have long insisted parliament be given the chance to veto any military moves.
Andrew Bridgen told The Huffington Post UK on Monday evening that he suspected a "large proportion" of Tory MPs remained to be convinced by the arguments for starting another "shooting war in the Middle East".
"We are fortunate we live a parliamentary democracy, not a dictatorship. Parliament should be recalled," he said. "I think it's for the foreign secretary and the prime minister to come to the Despatch Box and persuade the House of the need [for intervention]."
Earlier this year the North West Leicestershire MP organised a letter signed by 81 other Tories urging Cameron to grant a vote before any action was taken.
In something of an understatement, Bridgen said given past assurances from the government that there would be a vote, the failure to hold one would provoke "consternation" among backbenchers.
His view was shared by Peterborough MP Stewart Jackson. The backbencher, who is also sceptical about the wisdom of intervention, told HuffPost UK: "I back a recall of parliament and there must be a debate and vote before any substantive UK involvement in the civil war."
Cameron is due to chair a meeting of the National Security Council (NSC) on Wednesday to discuss potential responses to the deadly attack after breaking off his family holiday in Cornwall to return to Downing Street. Nick Clegg has also cancelled a trip to Afghanistan to attend the meeting.
On Monday evening US secretary of state John Kerry said evidence of the use of chemical weapons was already "real and compelling" and indicated further evidence would be unveiled soon.
In an emotive address that ratcheted up the rhetoric against Assad, Kerry laid the blame for the attack at the feet of the regime and said it was a "moral obscenity" that "should shock the conscience of the world".
Soon after, White House press secretary Jay Carney told reporters there was "very little doubt that the Syrian regime is responsible for this attack" and that Obama was "assessing a potential response".
Carney said: "All of us who have seen the physical evidence are repulsed by it. Indiscriminate killing of innocent women and children in an attempt to maintain his bloody grip on power is despicable, but that's what we have come to expect from Bashar al-Assad."
In London, Downing Street said Cameron told Russian president Vladimir Putin on Monday that there was "little doubt that this was an attack carried out by the Syrian regime".