Here are some of the key quotes from the debate over military action in Libya in the UK House of Commons:
PRIME MINISTER DAVID CAMERON (1532 GMT)
It's quite clear the population of Benghazi was under heavy attack. Civilians were being killed in significant numbers (and) an exodus from the town had begun. There was an urgent need to stop the slaughter... If Gaddafi's attacks on his own people succeed Libya will become once again a pariah state festering on Europe's border, a source of instability, exporting terror beyond her borders...
A successful outcome is the enforcement of the will of the UN, which is a cease of attacks on civilians. In Iraq, we had been prepared to go into a country, to knock over its government and put something else in place - that is not the approach we are taking here.
LABOUR LEADER ED MILIBAND (1616 GMT)
We are a generous and compassionate people, but there will no doubt be people in parts of the country - and, we have heard, in parts of this House - wondering if it really needs to be us, now. It is a valid and important question. But... we have to make a judgment about our role in the world and our duty to others. Where there is just cause, where there is reasonable action that can be taken, where there is international consent - are we really saying we should be a country that stands by and does nothing?"
FOREIGN SECRETARY WILLIAM HAGUE (2142 GMT)
This is not the West imposing its views on Libya; it is the world saying that the people of Libya should be allowed to express their views without their government setting out to slaughter them
ANGUS ROBERTSON, WESTMINSTER SNP LEADER (1537 GMT)
[The government must] stick to the terms of the UN resolution to address concerns about an open-ended commitment and the potential for mission creep.
ELFYN LLWYD, WESTMINSTER PLAID CYMRU LEADER (1815 GMT)
We are concerned the clear wording of resolution 1973 might become clouded - and this whole matter could be a smokescreen or shorthand for regime change, which would be unlawful under international law.
SIR MENZIES CAMPBELL, FORMER LIB DEM LEADER (1702 GMT)
I thought that the action against Saddam Hussein was illegal... but this action is necessary, legal and legitimate. It is necessary because of the systematic brutality of Colonel Gaddafi towards his own people, whose only crime is to want the opportunity to have a more democratic form of government.
JEFFREY DONALDSON, DEMOCRATIC UNIONIST PARTY (1753 GMT)
"If [Gaddafi] remains in power and that is a potential outcome of all of this, he has made clear he will seek to bring about retribution against those who have acted against him. We in this country know what that can look like, we know what it looked like in Warrington, we know what it looked like in Manchester, in Canary Wharf, in Bishopsgate, in Enniskillen, in Warrenpoint, on the Shankill Road in Belfast, where the weaponry that Gaddafi supplied to terrorists were used to bring to an end innocent lives of British citizens."
RORY STEWART, CONSERVATIVE MP, FORMER SOLDIER AND DIPLOMAT (1758 GMT)
The fact that this is not just an Arab country but a country with oil is something we have to bear in mind. The kind of legitimacy we might have had in Kosovo is going to be more difficult for that reason.
KRIS HOPKINS , CONSERVATIVE, FORMER SOLDIER (1728 GMT)
There's nothing glorious in war. There's nothing romantic about it. And I would say to some members of the media who have portrayed some form of entertainment about what's going on, and what has gone on in previous wars, it is just not right. I'm afraid human beings need to commit brutal savage attacks on each other to win wars.
JO SWINSON, LIB DEM (1809 GMT)
Not acting is not a neutral position to take, there are huge risks of inaction also, not least the bloodbath in Benghazi. Indeed in Gaddafi's own chilling words we heard exactly what would have happened, that he would give no mercy... it was very clear that his aim was also to terrorise his own people, to make them cower into submission.
DENNIS SKINNER, LABOUR (1603 GMT)
It's easy to get into a war; it's much harder to end it. When will all those nations that are taking part know what the circumstances are for pulling out and ending the war?
KATY CLARK, LABOUR (1835 GMT)
We are in a situation domestically where we are seeing huge cuts in public spending and indeed we are seeing huge cuts in the spending on military equipment. We need to think very carefully to what extent our constituents will feel that a long war and an expensive war, which follows on from previous conflicts, is something that they will support this Parliament in doing.
DAI HAVARD, LABOUR (1733 GMT)
We are still in Afghanistan. We need to get real about what we can and cannot do and we then need a conversation about the domestic effects of all this. There are domestic effects on the strategic defence and security review and other matters. Will we have the capability to operate in the littoral in the future?
STEPHEN GILBERT, LIB DEM (1931)
There is no such thing as a good war, but there is perhaps such a thing as a just war... standing up to this brutal warlord using our capabilities to protect civilians I believe we are doing the right thing today... We've seen an unprecedented grasp for freedom by people who no longer want to live under tyranny and fear.
EDWARD LEIGH, CONSERVATIVE (1957 GMT)
I voted against the Iraq war, because although it was ostensibly about dealing with weapons of mass destruction, in fact, as we know, it was about regime change. A lot of people have said that the current situation is very different, but is it? We are told that it is about humanitarian objectives, but is it not, in fact, about regime change, just as in Iraq? We need to ensure that our objectives are entirely and only humanitarian, and about protecting the people in Benghazi.
MARK LANCASTER, CONSERVATIVE, FORMER SOLDIER (1836 GMT)
I do fear that we will have to have further UN resolutions before we see the end of the situation in Libya. At best if I'm honest, I think what we have before us will probably get us to a stalemate. We will achieve much in preventing conflict in Libya, we will achieve much in preventing unnecessary human death, and for that this House should be very proud of this country's contribution in securing that resolution, but it will not be enough.
DAVID WINNICK, LABOUR (1841)
The fact of the matter is, you can't carry out the sort of military operation which is taking place without civilian casualties, so while we talk about protecting the people, and the reason, the justification for the operation, we have got to recognise at the same time, that many innocent people are going to be killed.
MADELINE MOON, LABOUR (1859 GMT)
It's been suggested that we shouldn't mention the SDSR (Strategic defence and security review) but over the weekend I certainly had lots of phone calls from members of the armed forces, who feel angry, who feel that we have had talks of cuts, and we have had talks of loss of platform and now those platforms are being brought into use.
ALUN CAIRNS, CONSERVATIVE (1913 GMT)
Our defence technology is impressive and astonishing, but judgement in using them must be taken in the context of the wider difficulties that they can bring over the longer term... Col Gaddafi is a master of propaganda and of using that propaganda to motivate some if his civilians... Outgunning Col Gaddafi in the moral, political and public means is as important as outgunning him by military means.
CAROLINE LUCAS, GREEN PARTY (2016 GMT)
We cannot ignore our own complicity in arriving at this point. We cannot continue to arm regimes that abuse their own citizens, and try to claim the moral high ground when addressing the conflicts that those same arms have helped to perpetuate.
DAVID LAMMY, LABOUR (2048 GMT)
I think of how this all began on 17 December 2010 with one man, Mohammed Bouazizi, who burned himself to death because of the oppression he saw and experienced in Tunisia. That set off a wave of activity across the Middle East. In supporting this, we line up with him and with the young people of the region, the 29% of the population aged between 15 and 29 who have had enough.
BOB STEWART, CONSERVATIVE, FORMER UN COMMANDER IN BOSNIA (2054 GMT)
What can we do to help? We cannot invade, we cannot assassinate -it is up to the Libyans to decide what we do. I have seen people with pitchforks try to take out tanks. How are those people going to be protected? They need help. Perhaps the Arab League could help a little more in that respect. Perhaps it could go forward. We cannot do it. Nobody knows the end game - we all realise that.
YASMIN QURESHI, LABOUR (2108 GMT)
We in this country and this House do not really understand the Middle East and north Africa. We are meddling in things that we should not meddle in, because there are so many uncertainties. In the past 10 or 12 years, America, ourselves and others have spent trillions of dollars on being involved in conflicts in the Middle East, and what have we left? We have not resolved any of the situations involved or made countries any better than when we went into them.
JOHN REDWOOD, CONSERVATIVE (1622 GMT)
How much intervention [is] it reasonable for the West to make in what is really a civil war in which the rebel side is in considerable difficulties?