28 August 2013
Last updated at 15:21 ET
A team of UN weapons inspectors has been back at the site of the alleged attack
The House of Commons will have to hold two votes before it can back “direct” military action in Syria, the government has announced.
MPs, returning early to Westminster on Thursday, will debate a motion on a “strong humanitarian response” to an alleged chemical weapons attack.
A second vote on military action will only happen after the UN has considered reports by its inspectors, it adds.
Labour said David Cameron had “changed his mind” under pressure.
The Syrian government has denied it is responsible for a suspected chemical weapons attack near Damascus on 21 August in which hundreds of people are reported to have died, blaming opposition forces.
UN inspectors have returned to the site of the suspected attack and secretary general Ban Ki-moon has said they need four days to finish their investigation there.
This means a second parliamentary vote could not happen until at least early next week.
Earlier, leader Ed Miliband had threatened to oppose the government’s motion until weapons inspectors had reported to the UN Security Council on their evidence.
Earlier on Wednesday, the prime minister gathered the UK’s military and security chiefs, along with key cabinet ministers, in Downing Street for emergency talks.
The National Security Council “agreed unanimously” on a recommendation, the details of which are not known, but which will be considered by the cabinet on Thursday.
MPs and peers will then debate and vote on the government’s motion.
The government’s motion states that “this House deplores the use of chemical weapons” by President Assad’s government alleged to have taken place last week, and says a response “may, if necessary, require military action that is legal, proportionate and focused on savings lives by preventing and deterring further use of Syria’s chemical weapons”.
The motion also accuses the United Nations of a “failure” to deal with the Syrian crisis, but says the government believes “that a United Nations process must be followed as far as possible to ensure the maximum legitimacy for any such action”.
Before the motion was published, Labour put out its own amendment, saying it would “only support military action involving UK forces” if various conditions were met – including allowing UN weapons inspectors time to report to the UN Security Council, and on the condition they produce “compelling evidence that the Syrian regime was responsible”.
The government effectively agreed to this when it published its motion.
It says “the United Nations Security Council must have the opportunity immediately to consider” the inspectors’ findings.
“Before any direct British involvement in such action a further vote of the House of Commons will take place,” it adds.
Earlier, the UK put a suggested resolution to the five permanent members of the UN Security Council “authorising all necessary measures to protect civilians” in Syria.
It called for military action against what Britain has termed Syria’s “unacceptable” use of chemical weapons.
Syria has accused the West of “inventing” excuses to launch a strike.