Voting 524 to 43, British lawmakers overwhelmingly supported airstrikes against IS militants, giving green light to military intervention in Iraq, Xinhua reported.
British Prime Minister David Cameron demanded a recall of parliament to debate on British involvement in US-led airstrikes in Iraq after the Iraqi government asked Britain to help fight the IS, also known as ISIL.
In his address to parliament, he said IS posed a threat to the "streets of Britain" and Britain had a "duty" to confront it militarily.
The prime minister said there was a strong case for Britain joining in the airstrikes against the militant group, according to a BBC report, which added that Cameron also warned members of parliament that the fight would "take years, not months".
"...We should be in no doubt that future British prime ministers and future British governments, I suspect, will be standing at this despatch box, dealing with this issue of Islamist extremism in different forms and in different parts of the world for many years to come," he said.
Joining airstrikes against the IS would be "clearly lawful", Cameron said. "I don't believe there is a legal barrier because I think the legal advice is clear that - were we to act or others to act - there is a legal basis."
He said Britain wanted to support its "Muslim 'friends' reclaim" their religion.
"We are dealing here with a generational struggle caused by the perversion of one of the world's great religions, Islam," the Guardian quoted him as saying.
"We will play our part in destroying these evil extremists, we will support our Muslim friends around the world as they reclaim their religion... our inspirational armed forces will put themselves in harm's way to keep our people and our country safe."
On Tuesday, Cameron supported the latest airstrikes against IS carried out by the US and five other countries from the Gulf and Middle East. Britain is already offering military support, including supplying arms to the Kurds and providing surveillance operations by a squadron of Tornadoes and other Royal Air Force aircraft, according to Downing Street. IANS