Britain's House of Commons voted to approve a motion which permits the Air Force to launch airstrikes against Islamic State (ISIL) jihadists in Iraq.
MPs voted 524 to 43 to approve the motion, submitted by the government of Prime Minister David Cameron, which does not sanction airstrikes in Syria, nor does it involve a ground offensive.
Another motion on Syria, where the US along with several Arab nations have already begun launching airstrikes, is expected to materialise.
Speaking in parliament on the motion, Prime Minister Cameron said "that this House condemns the barbaric acts of ISIL against the peoples of Iraq -- and the humanitarian crisis this is causing." He referred to "the clear threat ISIL poses to the territorial integrity of Iraq and the request from the Government of Iraq for military support from the international community and the specific request to the UK government for such support.
The UK also "further recognises the threat ISIL poses to wider international security and the UK directly through its sponsorship of terrorist attacks and its murder of a British hostage," he said.
"Is there a threat to the British people? The answer is yes. ISIL has already murdered one British hostage and is threatening the lives of two more.
"ISIL is a terrorist organisation unlike those we have dealt with before. The brutality is staggering: beheadings, crucifixions, the gouging out of eyes, the use of rape as a weapon and the slaughter of children... But it is not just the brutality; it is backed by billions of dollars and has captured an arsenal of the most modern weapons.
"This is not a threat on the far side of the world; left unchecked, we will face a 'terrorist caliphate' on the shores of the Mediterranean and bordering a NATO member." The decision comes two days after a speech Prime Minister Cameron gave at the UN General Assembly meeting, where he stressed that, "Britain will play its part," however adding that, "we must not allow past mistakes to become an excuse for indifference or inaction," in reference to both Iraq and Afghanistan.