Prime Minister David Cameron recalled Parliament today and made a case for the UK to join US-led air strikes against Islamic State (IS) terror network in Iraq which he warned could "not just take months but years".
Cameron told MPs that IS poses a "clear and proven" threat to British lives and was a "brutal", well-funded "terrorist organisation" that had destabilised Iraq and Syria.
"This is going to be a mission that will take not just months but years but I believe we have to be prepared for that commitment," he said while answering a question on the length and scope of the mission in the House of Commons debate.
He stressed that it was in the UK's interest to join in bombings in Iraq against IS and there was "no legal barrier" to similar action in Syria.
The strikes could be launched within hours of a Parliament vote on the issue as Cameron told MPs there is a "strong case" for UK military intervention in Iraq and Syria.
Cameron said that Islamic militants "have already murdered one British hostage" and are "threatening the lives of two more".
He said, "The brutality is staggering - beheadings, crucifixions, the gouging out of eyes, the use of rape as a weapon, the slaughter of children. All of these things belong to the dark ages.
"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 with a declared and a proven determination to attack our country and our people."
Parliament is due to vote on UK involvement at the end of a seven-hour debate in the House of Commons later this evening. If the vote is passed, the UK would join the US and France in launching targeted strikes on the IS group in Iraq.
All three main political parties in the UK – the Conservatives, Liberal Democrats and Labour –back UK military participation in bombings against IS in Iraq, which the coalition says is legal because it was requested by the Iraqi government.