Prime Minister David Cameron made a toned-down appeal for "action" against Syria in the House of Commons today, as many MPs expressed scepticism and then voted against his proposals.
The government motion was defeated 285 to 272, a majority of 13 votes. Mr Cameron said: "It's clear to me that the British parliament and the British people do not wish to see military action; I get that, and I will act accordingly."
Labour's amendment, which was seen in some quarters as a watered-down version of the government's, was also lost.
The Prime Minister had originally recalled parliament to push for agreement on punitive military strikes against Syria, but after huge pressure internally and externally to recognise the role of the UN and the current inspection regime, he conceded yesterday that two votes would be required - downgrading today's debate and division to an "in principle" one, subject to a range of qualifications.
As speaker after speaker posed serious questions about the strategic, tactical, legal, military and regional consequences of a strike, the Prime Minister was at pains to acknowledge "a valid point" and to stress that "no decision has been taken".
Mr Cameron also conceded that intelligence that the regime used chemical weapons is not "100 per cent certain" and he offered "no guarantees" in reply to questions about possible damaging repercussions of an attack.
Opposition leader Ed Miliband said he was neither resolved for nor against military intervention, but added that evidence was "key" and more of it was needed.
However, his own amendment, seeking a "clear roadmap for decision-making" was accused of differing little from what was on the table. He defended it by saying that determining "principles for decision making" was crucial.
Observers suggested that the performance of both leaders was illustrating the immense pressure they were under, with deep divisions on the issue across the main parties, and huge public concern about Britain becoming submerged in an escalating conflict.
A poll in the Telegraph newspaper this morning suggested that only 11 per cent of the population favour a military attack on Syria on the current terms.
The BBC oddly reported the headline speech as 'UK makes the case for Syria action', but the majority of speeches in the first four hours sounded very far from convinced, either of the case or of the argument that is was one that could command the support of the country as a whole.
The government published a short page-and-a-half summary of the Attorney General's legal advice, which was that military action would be a legal "humanitarian intervention", even without the endorsement of the UN Security Council.
However, James Arbuthnot, influential Chair of the House of Commons Defence Select Committee, questioned "at least one aspect" of the advice, specifically on the chances of a specifiable, successful outcome.
Meanwhile, Green MP Caroline Lucas said that the Responsibility to Protect (R2P), the basis for humanitarian intervention, was being misrepresented. It still had to be commissioned under the UN Charter, which made it clear that the UN's agreed mechanisms, including the Security Council, had to be respected and used.
There was a tendency she said, reflected in both the government and opposition motions, to treat international law and the UN as "inconveniences". He own, alternative proposal was not accepted by the Speaker, which she and others "regretted".
The government also published the letter of the chair of the Joint Intelligence Committee (JIC), which says that a chemical weapons attack did occur in Damascus last week (already a widely accepted fact) and that evidence gathered suggested that it is "highly likely" that Bashar Assad's regime was responsible.
However, the JIC admitted that a good deal of what it was putting on the record was from "open source reporting" (the media), that the actual intelligence was "limited but growing", and that "the regime’s precise motivation for carrying out an attack of this scale at this time" was frankly unfathomable.
It said that it did not believe that there were "plausible alternative scenarios" available, but restricted its observations about this to armed opposition rather than contending factions around the president and the regime acting independently for political purposes.
The JIC is made up of senior civil servants, security analysts and members of the security services.
Responding to the release of the documents this morning, Conservative MP Julian Lewis, who is a member of the parliamentary Intelligence and Security Committee, told the BBC's World at One that the JIC summary is "inconclusive".
He said that as he has advanced security clearance as a member of the committee, he would now like to see the actual intelligence on which the summary was based.
In a powerful speech in the Commons in the afternoon, Mr Lewis surgically dissected the contradictions inherent in the case for military intervention. If Assad had commissioned a major chemical weapons attack just before the arrival of UN inspectors, this was "highly irrational", he said. Yet we were being asked to believe that rational deterrence would work on him in further instances.
"He's bad enough, but is he mad enough?" asked controversial Respect MP George Galloway, who expressed revulsion both at the regime and opposition forces. He cited brutal killings of Christian priest and a bishop by insurgent groups.
Conservative MP James Arbuthnot also expressed disquiet at the "new doctrine of punishment" which appeared to underwrite a large part of the case for intervention.
Senior Labour MP Gerald Kaufmann made his opposition to armed action clear, and former Foreign Secretary Jack Straw expressed a range of concerns. In particular he said, President Obama's description of what was being proposed as a "shot across the bows" was either not what he really had in mind or something which could not have the effectiveness required.
The government's claims that a missile strike against Assad was "not taking sides" in a civil war were not could not be sustained, said Straw and several other speakers.
Conservative MPs in favour of military intervention said "something must be done" and "a stand" was necessary. They believed that a strike could dissuade President Assad from further abuses.
Andrew Mitchell MP claimed that NGOs "on the ground" were divided on the propriety of an armed intervention, but provided no evidence of those in favour, with a raft of charities urging caution over the past few days.
Mike Gapes MP, an opposition defence expert, set out a number of scenarios in which an attack on Syria could make the situation worse in relation to WMDs.
Jeremy Corbyn, Labour MP for Islington North, pressed the point that a further, serious engagement with both Russia and Iran was needed to move towards a political solution, "which is what we will have to have in the end".
Politicians from Scotland (SNP), Wales (Plaid Cymru) and Northern Ireland (the DUP, unusually) all made their concern and scepticism clear.
Perhaps the strongest note came from Julian Lewis MP (New Forest). He raised the spectre of global conflagration and referred to a series of possible escalations involving Israel, Iran, Turkey, Hezbollah, the US and others.
He reminded the House that the First World War could never have been predicted on the basis of the assassination of "an obscure archduke", but emerged from a whole series of reactions from that small event.
"I think it would be wrong, and more importantly counterproductive, to attack Syria," said Kate Hoey MP, saying that she did not believe that it would make the plight of the people better - it might well make it worse.
In a passionate speech, Conservative MP Cheryl Gillan (Chesma and Amersham) asked for cast iron undertakings from the government that a vote for their motion would not be interpreted as support for military action per se, and that a second vote will definitely be held.
The government was assumed to be likely to win the vote tonight after a concluding speech from Deputy Prime Minister Nick Clegg, but it is equally clearly on the back foot - and news came in at 22.32 that the government's motion backing in-principle military action has been defeated.
Rumours of a further recall on Saturday or Sunday have been circulating at Westminster, though this is now unlikely. Indications are that the US is in no mood to wait for further democratic deliberation, but the problem side of its political, military and legal equation has increased significantly.
* Letter from the JIC chair, Jon Daly (*.PDF Adobe Acrobat document): https://www.gov.uk/government/uploads/system/uploads/attachment_data/fil...
* More on Syria from Ekklesia: http://www.ekklesia.co.uk/syria