The unexpected defeat by a vote of 285-272 has plunged Cameron’s governing Conservatives into crisis, and the country itself into a deep debate on Britain’s role on the international stage.
"To see my country draw back from a coalition that is in favour of international law and take a decision to stand aside does not fill me with great joy,” the former Liberal-Democrat leader Paddy Ashdown said on British television Friday morning.
British Defence Secretary Philip Hammond gave an interview immediately after the vote in which he worried about reaction in Washington, saying the result would “place a strain on the special relationship” between the United States and Great Britain.
France was quick to say the outcome of the British vote will not affect its support for military action. But Germany has now apparently ruled the possibility out.
Here in Britain, critics say David Cameron and his advisors vastly underestimated memories of the Iraq war and the misinformation contained in the dossier on weapons of mass destruction during the run-up to the 2003 U.S.-led invasion.
"They clearly, clearly got it wrong because last Sunday they briefed very, very strongly that he would be able to intervene [in Syria]," political commentator Kevin McGuire told CBC News in an interview.
Some British critics say if Cameron had adopted a more measured approach — waiting for the report of the UN weapons inspectors — he may have won the vote.
Ed Miliband, leader of the opposition Labour party, accused Cameron of cavalier leadership.