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17:28 I'm going to conclude the live blog at this point. Thanks for reading.
17:19 The former foreign secretary Jack Straw is speaking now. He cites Rwanda and Bosnia and says that "doing nothing in the face of evil" is as fraught with consequences as "doing something".
17:11 The Labour MP Jim Dowd is making a strong speech in favour of the intervention. He says the action reflects the refusal of the British people to "pass by on the other side". Sitting next to him is David Miliband, who may speak later on.
17:01 Ming Campbell is speaking now. He recalls his opposition to the Iraq war but says this intervention is "necessary, legal and legitimate". It was essential to prevent a "slaughterhouse" in Benghazi, he says.
16:55 The former Labour defence secretary Bob Ainsworth says he is a "late and reluctant" supporter of the intervention. He says that it "cannot be sensible" for the Defence Secretary, Liam Fox, to suggest that Gaddafi could be personally targeted by the coalition.
16:52 The former Conservative foreign secretary Malcolm Rifkind is speaking now. He asks William Hague to clarify whether the rebels can be armed under the terms of the UN resolution.
He warns that the no-fly zone must remain even if Gaddafi accepts a genuine ceasefire. The danger is that the Libyan leader will break the ceasefire as soon as the allies leave, he says.
16:47 Miliband refers to the "humanity and solidarity" showed to his parents as refugees from Nazi Germany. His support for the motion reflects the lessons of this experience, he suggests.
16:44 The Labour MP Joan Ruddock asks Miliband to condemn the jingoistic language of the tabloids ("Blown to Brits"). The Labour leader replies that everyone must show "extreme care".
16:42 Miliband says he wants to see the back of Gaddafi, but that no one should be under any illusions about the terms of the resolution. There is no mandate for the removal of the colonel. He says that we cannot afford "mission creep", including "in our public pronouncements".
16:38 The Lib Dem MP Andrew George asks Miliband how he would define success. Miliband says that, for now, the best criterion we have for success is the enforcement of the UN resolution.
16:36 He adds that Gaddafi's threat to the people of Benghazi puts him in a "particular category".
16:32 Miliband echoes Cameron (and Tony Blair) and rejects the argument that because "we can't do everything, we shouldn't do anything". An imperfect world order is not an excuse for inaction, he adds.
16:31 The Labour leader says he has been "reassured" by the government that the mission will be well funded.
16:30 Miliband says that doing nothing would be a dereliction of "our duty, our history and our values".
16:27 Responding to Ming Campbell, Miliband says that this is an important moment for multilateralism.
16:25 Miliband says we don't always know "how it will end"; the same was the case in Kosovo. But it is right to intervene to save thousands of lives.
16:23 Responding to Jeremy Corbyn, Miliband says he supports a review of UK arms exports and says he will address the issue of "double standards" later in his speech.
16:19 Citing the failure to support anti-Franco forces during the Spanish civil war, Miliband says that it would "revolt the conscience" of the world if we failed to intervene.
16:16 Ed Miliband rises to speak. He says the three key criteria for intervention have been met; it is just, feasible and has international support.
16:13 Concluding his statement, Cameron says that "it is for the Libyan people to determine their future and their destiny". But he adds that there is no "decent future" for the country while Gaddafi remains in power.
16:12 Cameron tells the Conservative MP Robert Halfon that he will take all possible steps to protect British forces from the possible use of mustard gas by Gaddafi.
16:09 The PM says that the international system must plan now "for stabilising the peace that we hope will follow".
16:06 Cameron says he has limited information on the Libyan opposition but that the evidence suggests they are "ordinary" people who want freedom, justice and liberty.
16:02 The Labour MP Dennis Skinner asks when we will know what the "circumstances are for pulling out". Cameron says the operation will end when we have "complied with and implemented the UN resolution". Once more, he emphasises that this is "different to Iraq".
15:58 Cameron says this will not be "another Iraq" because there are millions in the Arab world who want to know that the international community "cares about their suffering" and who support the intervention.
15:55: Cameron says that it is important to reassure the Commons and the country that "this is not an invasion". He emphasises again that the UN resolution prevents an "occupying force".
15:53 The Green Party leader, Caroline Lucas, says our response would be more "consistent" if we stopped selling arms to "reprehensible regimes".
Cameron replies that the government has revoked all arms export licences to Libya and agrees that "there will be lessons to learn from this conflict".
15:50 The Conservative MP John Baron asks Cameron why we haven't let "Arabs take the lead"; we've sold them enough weapons, he suggests. Cameron says that in order to act quickly, the campaign required participation by the US, the UK and France.
15:49 The Labour MP John McDonnell asks Cameron for a "categorical assurance" that the coalition will not use depleted uranium or cluster bombs. The PM replies that he has already given this guarantee.
15:45 The Labour left-winger Jeremy Corbyn asks Cameron to respond to criticism of the operation by China and India. Cameron says it was not possible to "wait and see". "We have waited and we have seen," he argues.
15:43 The PM returns to his statement after allowing several interventions. He announces that Spain, Canada, Norway, Denmark, Italy and Greece have all offered active support.
15:41 Cameron is asked to guarantee that ground troops will not be deployed. He says the UN resolution clearly rules out an "occupying force".
15:36 The SNP's Westminster leader, Angus Robertson, asks Cameron to respond to fears of "mission creep".
The PM says he's made it clear that Muammar Gaddafi needs to go but that "Libyans must determine their own future". The coalition's job is to enforce the UN Resolution.
15:34 Cameron adds that the allies prevented a "bloody massacre" in Benghazi "in the nick of time".
15:33 John Bercow says that 62 MPs have asked to speak in the debate. There will be a six-minute limit on speeches.
15:32 Cameron begins his statement. He announces that coalition forces have "largely neutralised" Libyan air defences and that a no-fly zone has been put in place.
15:22 Stay tuned for live coverage from 3.30pm.