International chemical weapons inspectors finally set to visit site of the alleged attack in Douma.
The prime minister’s advisers believe the result shows she has successfully navigated difficulties arising from her move to push ahead with a military operation without first consulting MPs.
But Jeremy Corbyn used the debate to demand that the House of Commons “take back our control” of decisions to launch any military action, with a new “War Powers Act”.
The development came as inspectors were set to finally make it to the site of the alleged Douma chemical weapons attack on Wednesday, with Ms May accusing Moscow of preventing the scientists from doing their work.
Ahead of the Commons vote on Syria, Ms May told MPs that coming to parliament before undertaking military action would “compromise the effectiveness of our operations and safety of British servicemen and women”.
She attacked the suggestion of a War Powers Act, claiming it would remove “vital flexibility” from situations which are “by definition unpredictable”.
She went on: “Making it unlawful for Her Majesty’s Government to undertake any such military intervention without a vote would seriously compromise our national security, our national interests, and the lives of British citizens at home and abroad.
“And, for as long as I’m prime minister, that will never be allowed to happen.”
She concluded by saying that after two days of debate no one could doubt her commitment to be held accountable by parliament, and also that the tone of the debate had been supportive to the strikes.
A vote related to the Syria action was already won by the government on Monday, though it was not on a substantive motion – one that explicitly seeks to approve the action or not.
The motion of Tuesday’s vote, which stated the Commons has “considered parliament’s rights in relation to the approval of military action by British forces”, was also neutral in tone.
But Mr Corbyn called on his own MPs to vote against it, despite Labour having called the debate, to show opposition over how they believe the government sidelined parliament in relation to the military action.
Before the motion was passed by 317 to 256, Mr Corbyn’s speech was met with bad tempered heckling from Tory MPs, who consistently tried to intervene while the Labour leader was talking.
Speaker John Bercow gave warnings to Conservative backbenchers such as Alec Shelbrooke and Mark Harper during the course of the debate.
Outlining his proposed War Powers Act, the Labour leader said it was for the Commons “to take matters into its own hands and take back our control”.
He added: “There’s no more serious issue in decisions made by parliament on matters of war and peace, and the government taking planned military action.
“That convention was established in 2003, it was enshrined in Cabinet in 2011, and the then the foreign secretary gave every indication that he supported the principle of parliamentary scrutiny and parliamentary approval of such a major step.
“I’ve outlined the caveats that are there in a case of overriding emergency, but I do think it is very important that the House of Commons, as one of the oldest parliaments in the world, holds the government to account.”
Earlier in the day the prime minister accused Moscow of preventing inspectors for the Organisation for the Prohibition of Chemical Weapons (OPCW) from reaching Douma.
Russian officials at OPCW headquarters in The Hague later said arrangements were being made for the inspectors to travel to the site on Wednesday.
Russian foreign minister Sergey Lavrov has flatly denied that Russia had “tampered” with the evidence, and insisted there is no proof that chemical weapons had even been used in Douma.
The Russian ambassador to Ireland warned that his country is losing “the last bit of trust” it had with the West, describing this as a “very dangerous development”.
Speaking at a press conference in Dublin, Yury Filatov suggested the strikes were intended to impede the investigation so nobody would know the truth, adding that experts have not yet found any traces of chlorine or any other toxic agents.
“As far as we can see there was no attack,” he said. “Not a single local resident was able to confirm that a chemical attack had actually taken place.”
Mr Filatov said the suspected chemical attack had “definitely been staged”, and that the images had been “fabricated”.