Britain can still make a difference in Syria, Labour leader Ed Miliband wrote today after he voted against the Government's motion on the principle of military intervention in the country.
Writing in the Guardian, Mr Miliband said the UK's global position lies in a "hard-headed multilateralism".
He added: "We must use next week's G20 meeting in Russia, with the eyes of the world on Syria, to seek to bring the international community together, and force the warring parties into the political solution that is necessary.
"But the vote remains an important moment: for parliament, for the country and for Britain's relations with the world.
"This moment also gives us the opportunity to learn the right lessons for the conduct of foreign policy across all parties".
The United States "values the special relationship" with the United Kingdom, the White House said in a statement.
The president spoke with Prime Minister Cameron today as part of their continuing consultations on the Assad regime's use of chemical weapons on August 21, which they agree is unacceptable and cannot be tolerated.
As always, the United States values the special relationship with the United Kingdom, a close ally and friend.
The president and Prime Minister agreed to continue to consult closely on Syria and the broad range of security challenges that our two countries face together.
Spoke to Secretary Kerry. He thanked me for the UK's steadfast friendship. United on ending #Syria conflict and use of chemical weapons
Downing Street has insisted that the US special relationship is still intact, despite Britain's MPs voting against military action in Syria.
David Cameron and President Barack Obama spoke on the phone about the Syrian crisis this evening.
In a statement, Downing Street said: "President Obama said he fully respected the PM's approach and that he had not yet taken a decision on the US response."
"They agreed that their co-operation on international issues would continue in the future."
US President Barack Obama told David Cameron he "fully respected" the approach the Prime Minister has taken over Syria in a telephone call tonight, Downing Street said.
The PM insisted he still wants to see a strong response to the chemical weapons attack on the outskirts of Damascus during the 15-minute discussion following the Commons defeat that has ended any possibility of British military intervention.
Could the evidence John Kerry has just revealed could it have swayed a few, or could better party management have swayed others? The Government only lost by 13 votes.
President Obama and the Prime Minister spoke by phone just under an hour ago.
The President was reassuring the Mr Cameron that the Americans saw this really as a single issue and that it would not sour the rest of the relationship, but what one insider told me this afternoon will really hurt - is the sight of the French acting with the Americans as this plays out.
I don't doubt that the 'special relationship' has been seriously damaged by this, it generated real dismay at the White House yesterday. The biggest disappointment to a British decision that I can remember in my years reporting from Washington.
But the real anger is aimed at Ed Miliband. It is judged by White house officials that he put party politics before a major transatlantic strategic decision.
And we are left with that irony that France the country that most vociferously opposed the Iraq war may be America's only ally in this one.
I think there is no doubt that America is going to strike it is regarded here that in action is really going to have major consequences.
It is also felt that the creditability of the Presidency is at stake.
And as John Kerry said this is also designed as a message to dictators all around the world.
The Prime Minister accused Ed Miliband of "siding with" the Russian Foreign Minister and "letting down America" over Syria, a Labour source told the Guardian.
The newspaper said Mr Cameron made the comments during a phone call with the Labour leader a day before a Commons vote on the principle of military intervention in the war-torn country.
Labour leader Ed Miliband told ITV News he did not regret voting against the Government's motion on the principle of military intervention in Syria.
He said: "What I wasn't willing to do, and I think the British people agree with this, was for Britain to engage in a rush to war, ill thought through military action without regard for the possible consequences."
A House of Commons spokesperson said: "Both divisions proceeded as normal last night, with division bells and the usual audio/visual indications on the hundreds of monitors around the estate.
"The division bells have been tested this morning and are working correctly."
The spokesperson added: "There would have been a lot of activity there around those (meeting) rooms.
"I think it would have been clear that there had been a division on and those involved would have known there was a division on as well."