Cameron backs down on urgent Syria strikes Senior sources had previously suggested that Britain would take part in strikes as soon as this weekend which meant an emergency recall of Parliament was necessary on Thursday. However, following Labour threatening not to support the action and senior military figures expressing concerns over the wisdom of the mission, the Prime Minister on Wednesday night agreed to put British involvement on hold. The climbdown is likely to be seen as an embarrassment for Mr Cameron as he was determined to play a leading role in British military strikes, which had been expected this weekend. The new strategy emerged after days of wrangling with Ed Miliband, the Labour leader, and after a succession of senior Tories had spoken out in the strongest terms against an intervention. There were growing doubts that Mr Cameron would be able to secure a Commons majority before the UN reported back on last week's gas attacks in Damascus that killed hundreds and injured thousands more. Protesters gather on Whitehall outside Downing Street to campaign for no international military intervention in the ongoing conflict in Syria (Getty Images) Labour had demanded the Prime Minister agree to hold a second vote in the Commons after the UN inspectors concluded their work. However, during a tense telephone call between the two party leaders at 5.15pm Mr Cameron "totally ruled out" giving MPs a second vote - which would have left Downing Street's plan for a weekend offensive in tatters. Labour then immediately announced that it would order its MPs to vote against the Government's motion authorising military strikes. Just minutes before 7pm Downing Street was forced to redraft the planned motion saying that "before any direct British involvement ... a further vote in the House of Commons will take place." On Wednesday night, a senior Conservative source said: "Labour has been playing politics when they should have been thinking about the national interest. Their position has changed continuously over the last 24 hours - finally ending in demands they had never even hinted at before. The Americans were consulted before Mr Cameron's decision was announced and senior White House officials are said to have made it clear that they "respect the British Parliament." The move came just three hours after William Hague, the Foreign Secretary said it was "very important" for the UK not to leave it too long before launching strikes against Bashar al-Assad's regime. MPs will still debate and vote on a broader motion in the Commons on Thursday. They will be asked to support the Government's motion which states that a "strong humanitarian response is required from the international community and that this may, if necessary, require military action that is legal, proportionate and focused on saving lives by preventing and deterring further use of Syria's chemical weapons." However, crucially the motion then adds: "Before any direct British involvement in such action a further vote of the House of Commons will take place." Nick Clegg, the Deputy Prime Minister, said: "We are ensuring the House of Commons has the final say before any direct British involvement - one vote tomorrow, and another one if and when we are asked to participate directly." UN weapons inspectors are not due to leave Syria until Friday, making it unlikely a second vote will take place before next week. Government sources said it was not inconceivable a second vote could be held late on Friday or even on Saturday. Ahead of Thursday's vote, MPs will be given a dossier of evidence by Downing Street that Whitehall sources have described as "utterly compelling" proof of Assad's involvement in chemical atrocities against his own people. It will include details of YouTube videos believed to show atrocities being committed by the Syrian regime. Mr Hague had on Wednesday reiterated that Britain must react urgently to do "what is necessary" to protect civilians and prevent further chemical weapons attacks by Assad's regime. Nato indicated its strong backing for Britain and the United States by saying that the Syrian regime's use of chemical weapons "cannot go unanswered." Mr Cameron had drawn up plans to force his MPs to back a motion that the party's whips are said to have warned was leading to anger among a growing number of backbenchers. Several junior members of the Government have spoken publicly over their concerns and there were indications that there could have been resignations if a compelling case for British involvement was not made. Guy Opperman, parliamentary private secretary to Mark Harper, a Home Office minister, said that he was not in favour of "any military action." "For my part I see no plan, as yet, and more importantly, no strategy and exit," he wrote on his website. Other Conservative MPs including Sir Gerald Howarth, a former defence minister, Nick de Bois, the secretary of the powerful 1922 committee and Richard Drax, a former soldier, also expressed serious concerns. Tory grandees joined former military leaders and high-profile church figures to warn of the dangers of intervening. However, Mr Cameron's decision to delay also attracted criticism from within his own party. Douglas Carswell, a Conservative MP, mocked the government's climbdown. He said: "What to do when you cannot command a majority in Commons for Syria strikes? Table motion about something else. This is how we are governed. The team of 20 UN inspectors has been in Syria since Aug 18 looking into three earlier suspected chemical attacks. Lakhdar Brahimi, the UN and Arab League special envoy to Syria, said the death toll from the "substance" used in last week's attack - widely thought to be the nerve agent sarin - could rise to about 1,000.