Against all expectations, the government motion on Syria was dramatically defeated by 285 votes to 272 tonight. Amid cries of "resign!" from Labour MPs, Ed Miliband asked a visibly chastened Cameron to reassure the Commons that he would not use the royal prerogative to approve military action, he replied:
Let me say the House has not voted for either motion tonight. I strongly believe in the need for a tough response to the use of chemical weapons, but I also believe in respecting the will of this House of Commons. It is very clear tonight that while the House has not passed a motion, it is clear to me that the British parliament, reflecting the views of the British people, does not want to see British military action. I get that and the government will act accordingly.
In a competitive field, this is the most extraordinary political event since the general election. No prime minister on record has been defeated on a matter of peace and war; Cameron's authority has been incalculably weakened. With around 30 Labour MPs absent from parliament, it was his own backbenchers who inflicted this defeat.
Labour's amendment was earlier rejected by 332 votes to 220. The irony is that had Cameron swallowed his pride and supported it (or incorporated Miliband's demands into the government motion), the possibility of military action would have been kept open. But after tonight's events, it has surely been closed off.