British warplanes are poised to join international air strikes on the Islamic State terror group in Iraq after David Cameron told the United Nations that the UK was ready to play its part in confronting "an evil against which the whole world must unite". In what amounted to a rallying cry to MPs to back military action when Parliament is recalled tomorrow, the Prime Minister warned that Britain must not be so "frozen with fear" of repeating the mistakes of the Iraq War that it fails to take on the "psychopathic, murderous, brutal" jihadis.
Amid speculation that RAF planes could join US and French allies in bombarding IS targets as early as this weekend, Mr Cameron declined to discuss when the operation might begin or how long it would last, but acknowledged that it could take "quite a long time". He said he was "confident" of receiving support from the three major parties in the parliamentary vote, avoiding the embarrassment of a repeat of last year's defeat over plans to bomb Syria.
Speaking to reporters in New York, Mr Cameron made clear that he envisages British warplanes joining coalition air strikes within Iraq, after receiving a request for military help from the country's new prime minister Haider Abadi, and stressed that there would be no "boots on the ground".
Islamic State - also known as Isis or Isil - posed a "clear and present danger to the United Kingdom" and the Baghdad government's invitation gave "a clear legal base" for British military action, he said. But he did not rule out later extending operations to IS strongholds in Syria - targeted by the US and its allies for the first time early on Tuesday - saying that this would happen only after a separate debate and vote in Parliament.
In a speech to the United Nations General Assembly on Thursday, Mr Cameron is expected to acknowledge the wariness felt by many in the international community over military action in Iraq, following the decade of violence which followed the US-led invasion of 2003. But he was expected to say it was vital to "learn the right lessons - Yes to careful preparation; no to rushing to join a conflict without a clear plan".
Mr Cameron is due to warn: "We must not be so frozen with fear that we don't do anything at all. Isolation and withdrawing from a problem like Isil will only make things worse. We must not allow past mistakes to become an excuse for indifference or inaction." Action against IS should be "comprehensive, intelligent and inclusive", working with partners in the region, potentially including Iran - whose president Hassan Rouhani he met for historic talks at the UN.
And he is expected to add: "We should be uncompromising, using all the means at our disposal - including military force - to hunt down these extremists."
The struggle with extremism must be waged not only against IS in Iraq and Syria, but also against Boko Haram in Nigeria, Al-Shabaab in Somalia, Ansar Al-Sharia in Libya and al-Qaida in Yemen, Mr Cameron is due to say. While the threat would not be best solved by Western ground troops "directly trying to pacify or reconstruct Middle Eastern or African countries", there was a place for the military in training, advising and supporting humanitarian missions, as well as in responding to the Iraqi government's request to the UN for support.
"My message today is simple," he is expected to tell the UN. "We are facing an evil against which the whole world must unite. And, as ever in the cause of freedom, democracy and justice, Britain will play its part." Mr Cameron's comments came after US president Barack Obama issued a plea to the international community to come together to "dismantle this network of death".
Speaking to the General Assembly, Mr Obama said that IS understood only "the language of force" and called on those who have joined up to fight with the group to "leave the battlefield while they can". The president condemned atrocities against women and religious minorities in IS-controlled areas and described the beheading of hostages including British aid worker David Haines as "the most horrific crimes imaginable".
Cameron, left, addresses a meeting of the United Nations Security Council
"No God condones this terror. No grievance justifies these actions. There can be no reasoning - no negotiation - with this brand of evil," said Mr Obama. "The only language understood by killers like this is the language of force. So the United States of America will work with a broad coalition to dismantle this network of death."
Addressing the fears expressed by the family of British hostage Alan Henning, who have said UK air strikes could increase the danger to his life, Mr Cameron told reporters: "It's a desperate situation, but let's be clear about two things. One is that we are dealing with psychopathic, murderous, brutal people who will stop at nothing to carry out dreadful acts on these hostages.
"And secondly, it's very important that we do the right thing as a country and we stick to the path that I set out some weeks ago about having a comprehensive strategy including all the elements at our disposal - humanitarian aid, diplomacy and also, where appropriate, military action. That's the way in which we are proceeding."
Asked whether wanted to see justice served on the Briton, nicknamed "jihadi John", believed to be responsible for three beheadings, Mr Cameron replied: "I'm not sure I can describe in words what I'd like to happen to him. He should see justice one way or another." Mr Cameron backed a UN resolution tabled by the US to stem the flow of foreign fighters enlisting in conflicts overseas, including by withholding passports and freezing assets.
Addressing the Security Council, the Prime Minister said IS had behaved with "medieval barbarity". And he added: "One of the most disturbing aspects is how this conflict is sucking in our own young people, from modern, prosperous societies. The threat to our security from foreign fighters is far greater today that it has ever been in previous conflicts."
The 12,000-plus recruits - including 500 Britons - who have flocked from around the world to join Islamic State were "a small army, brainwashed and turned into fanatics determined to harm their own countries", he said. Deputy Prime Minister Nick Clegg and Labour leader Ed Miliband each confirmed that they would be backing the PM's call for military action in Friday's vote.
Mr Miliband - who spoke with Mr Cameron before the recall was announced and has been briefed by national security officials - said: "We will learn the lessons of the past - but we will not turn away from threats to our national interest."
Meanwhile, after a meeting of Friends of Syria at the UN summit, Philip Hammond said the UK had pledged a further £16m to support the opposition to President Bashar Assad in Syria, taking the total to £46m. The Foreign Secretary said: "The President of Syria National Coalition, Dr Hadi al Bahra, addressed the meeting and explained the situation on the ground in Syria and set out his vision for a future, pluralistic Syrian politics rejecting sectarianism and disunity.
"We reaffirmed, as Friends of Syria, our strong support for that vision. Many countries committed additional resources. I announced that the UK would be increasing our commitment to £46m, delivering practical support to opposition governance in areas that the moderate opposition controls and to bolster regional resilience to extremism."