Defence secretary Michael Fallon has suggested that the campaign against IS could be a “long haul” of “two to three years”.
David Cameron discussed the situation with senior ministers ahead of an emergency Commons vote on the military intervention today.
Downing Street last night released the wording of the motion that will be put before MPs, along with a summary of the legal justification for airstrikes.
The motion text states that troops will not be deployed in “ground combat operations” against IS. It also makes clear that another vote will be called if the campaign is to be extended to Syria.
The legal summaryargues that the action is permissible because Iraq has requested military help to protect its “people and territory”.
Fallon told The House magazine: “John Kerry has estimated two to three years — that looks like a long haul to me.
“But we have to face up to this. This kind of extremism has been spreading, taking root in democracies.
“I was really struck at the Nato summit by countries as far apart as Norway and Australia concerned about returning fighters, about the threat from reimporting terrorism.
“We all have a very direct interest. Britain does above all, we’ve already seen terrorist attacks here, the London Tube, London buses, the murder of Lee Rigby, the attack on Glasgow airport, we’ve already been under attack from this kind of extremism and we have to deal with it.
“This is a very direct British interest and our armed forces are ready for it.”
Meanwhile, radical cleric Anjem Choudary was arrested in a series of dawn raids along with eight other men on suspicion of supporting a banned terrorist group.
The men, who were all seized in London, were arrested on suspicion of being members of, or supporting, extremist organisation al-Muhajiroun, as well as encouraging terrorism.
Lawyer-turned-preacher Choudary was detained shortly after firing out a series of anti-Western messages at 5am on Twitter, including claims that the definition of terrorism was “more suitable for the US/UK policy in Muslim lands”.
Sweet shop Yummy Yummy, owned by Choudary’s brother Yadzani, in Whitechapel east London was one of 18 properties searched across London, while another address in Stoke-on-Trent, Staffordshire, was raided.
A nearby resident said Choudary had recently moved out of the area.