London: Britain should join air strikes against the ISIS in Syria and should not "sub-contract" its security to allies, Prime Minister David Cameron said on Thursday in a written statement to MPs.
"I believe that we should now take the decision to extend British air strikes against ISIS into Syria," he wrote, ahead of a speech in parliament today where he will formally argue his case for war.
Cameron said that it was in Britain's national security interests to strike ISIS terrorist and deny them a "safe haven" in Syria, arguing that the burden should not fall only on Britain's allies.
"It is wrong for the United Kingdom to sub-contract its security to other countries," he said.
"We have to deny a safe haven for ISIS in Syria. The longer ISIS is allowed to grow in Syria, the greater the threat it will pose," he added, using another name for ISIS.
Cameron is expected to call a vote in parliament on the issue before recess begins on December 17.
He has stepped up pressure for MPs to back joining air strikes in Syria after ISIS claimed responsibility for the November 13 attacks in Paris, which killed 130 people.
Cameron on Monday visited Paris, where he met President Francois Hollande and paid tribute outside the Bataclan concert venue, where 90 people were killed.
"I firmly support the action President Hollande has taken to strike ISIS in Syria," Cameron said after talks in Paris.
"It's my firm conviction that Britain should do so too."
While British forces are taking part in air strikes on ISIS targets in Iraq, they are not involved in the US-led coalition targeting Syria due to resistance from opposition parties still mindful of previous unpopular interventions in Iraq and Afghanistan.
Labour's anti-war leader Jeremy Corbyn is against any military action but Cameron appears increasingly confident he can get enough support from Labour MPs to pass the vote, particularly after last week's UN Security Council resolution authorising countries to "take all necessary measures" against ISIS.
A Times/YouGov opinion poll last week found that 58 percent of people would approve of Britain joining air strikes in Syria, compared to 22 percent against.
Reports suggest the government could call a vote on the issue next week.
Cameron on Monday only said that the vote could come "in the coming days and weeks".
