Former foreign secretary and Conservative peer Lord Hurd of Westwell tells the Lords there is "a terrible clarity" which has revealed IS as a plague comparable to the Black Death.

Darren Westwood from Birmingham: "There will be no British troops on the ground in Iraq" remember those words at the next election. We all know this is the beginning of another full scale war.

Labour MP Dai Havard stresses the importance of diplomacy, saying there is a possibility of "some soft of rapprochement" between Iran and Saudi Arabia.

"It's dirty busy - diplomacy always is. You sometimes have to speak to people you don't want to speak to, to make progress," he says.

As MPs and peers debate the UK's involvement in Iraq, the US-led coalition continues its action against IS.

• The United States confirms three new strikes in Syria overnight targeting IS positions in the eastern province of Deir al-Zour.

• Spanish and Moroccan police arrest nine people suspected of belonging to an IS-linked militant cell based in the Spanish enclave of Melilla, on the north coast of Africa.

• Danish government announces it will be joining the military operations against IS - but only in Iraq. It will be sending seven F-16 fighter jets.

Dominic Casciani
Home affairs correspondent, BBC News

We've had a lot of powerful talk in the House today about why the UK needs to be doing more to combat radicalisation and extremism. Here's an explainer on how the government's recent proposals for new terrorism powers aim to disrupt plotting by anyone returning from Syria and Iraq - and why some critics says there needs to be a plan that goes beyond just prosecutions and jail sentences.

The first speaker in the Lords to oppose military action is Lib Dem Baroness Falkner of Margravine, who sits on the National Security Strategy Committee.

She says "we're rushing into action" when "US firepower is more than adequate to degrade ISIL" even without the assistance of Arab countries or the UK.

Labour's Lord Reid of Cardowan, former home secretary and defence secretary, makes the case for supporting military measures with public services such as education and sanitation which he says will constitute "a real intervention to defend the winning of the peace".

Angelina in the UK: "I disagree with the stance on Iraq as air strikes will escalate the violence. As for bombing Syria, this is also a foolish move, because the country is in a civil war and more conflict will not ease the problem. How about diplomacy instead of this constant war mongering? I disagree with the opinion that bombing ISIS will decrease the conflicts. I may be a dreamer, but I believe in peace and that can only be achieved via diplomacy, communication and treaties."

The UK must also act economically - and stop financial flows to the IS, Liam Fox tells the Commons.

"We've got to stop groups in the region playing a double game - and publicly decrying them but providing them with the funding that they require," he says.

He adds that it is a mistake not to include Syria in the motion, stressing that the group operates from Syria and attacks "the Iraq state itself from Syria". He believes there is a legal case to attack Isil bases in Syria - and warns that "sooner or later" this will have to happen.

Former Conservative Party leader Lord Howard of Lympne also supports UK participation in military action, asking "what kind of country would we have become" if we didn't intervene.

Speaking in support of UK action, Liam Fox - Conservative former defence secretary - says IS threatens to destabilise the entire region and will become "global exporters of jihad if we allow them".

He says greater regional support is needed than at present, including Turkey, which he describes as a key player in the region, and a strong Nato ally.

Green MP Caroline Lucas has issued a statement opposing air strikes: "The hateful ideology of ISIL must be stopped.

"But I've yet to be convinced, from the evidence I've heard so far, that military strikes will be effective in achieving that. Ultimately we need a political solution - ISIL represents an ideology; killing people rarely kills their ideas. To the contrary, it more often fuels them."

Labour MP Alison McGovern asks whether the UK can do more to help refugees in the regime. She says the UK has a "moral duty" to help the innocent victims of the conflict.

The Archbishop of Canterbury stressed the need to win the religious and ideological argument, observing that for some young Muslim the lure of extremism "outweighs the attractions of a consumer society" and warns that if we don't address that "we will fail in the long-term".

It's clear from the debate so far that the legacy of the 2003 invasion of Iraq is still fresh in MPs' minds. Many references have been made to the UK's involvement in that war. This was also the case during last year's debate on possible military action against Syria in response to allegations of chemical weapons being used against civilians- in which MPs voted against action.

Labour MP Stella Creasy tweets, external: Powerful words from @Alison_McGovern who argues it is our job to make sure the future is not like the past when it comes to #iraq

The Archbishop of Canterbury, the Most Revd Justin Welby, tells peers: "We do need to take this action now."

He calls on religious leaders to "up their game" in order to offer a "more remarkable hope than ISIL".

Sir Ming says the language in the debate so far has been about "destruction", but, he says, "I am not sure it possible to destroy an ideology."

However, you can adopt "containment and deterrence" by degrading military capabilities, he counsels, and voices support for UK action. Sir Ming's comments are cut short by the speaker, as he exceeds the five-minute time limit.

Foreign Office minister Lady Anelay tweets, external: Briefed Parliamentary colleagues on #ISIL this morning. Clear threat posed to UK & international community requires strong, united response.

Conservative MP Graham Evans tweets, external: @HazelBlearsMP making very powerful speech making the good point about radicalisation of young Muslims in the UK.