David Cameron: Some Muslim communities 'quietly condone' extremist ideology – instead of confronting it

His intervention follows the death in Iraq of a suicide bomber and the disappearance of three sisters who are believed to have travelled to Syria

The Prime Minister's comments come at the beginning of the Muslim holy month of Ramadan, and will be seen as controversial (Getty)

Parts of some Muslim communities have to share the blame for young Britons joining Isis forces because they have “quietly condoned” extremist ideology instead of confronting it, David Cameron will argue.

His provocative intervention follows the death in Iraq of a 17-year-old old suicide bomber from Dewsbury and the disappearance of three sisters from Bradford who are believed to have travelled to Syria.

Its timing, at the beginning of the Muslim holy month of Ramadan, will also be seen as controversial, but Downing Street said he was determined that all sections of society debate the factors which spur young adults to head to Syria or Iraq to become Isis fighters or “Isis brides”.

Speaking at a security conference in Slovakia, Mr Cameron will argue that impressionable young people can slide into violence when “Islamist extremist ideology” – such as viewing women as inferior and homosexuality as evil – is not challenged by community leaders.

“We’ve always had angry young men and women buying into supposedly revolutionary causes. This one is evil, is it contradictory, it is futile – but it is particularly potent today. I think part of the reason it’s so potent is that it has been given this credence,” he will say.

“So if you’re a troubled boy who is angry at the world or a girl looking for an identity, for something to believe in and there’s something that is quietly condoned online, or perhaps even in parts of your local community, then it’s less of a leap to go from a British teenager to an ISIL fighter or an ISIL wife than it would be for someone who hasn’t been exposed to these things.”

He will argue that families and communities as well as the government and the police have to do more to prevent the process of radicalisation and confront the “poisonous ideology” of Isis, which represents “one of the biggest threats our world has faced”.

He will warn this week’s cases highlight the ease with which young people can slide non-violent to violent extremism.

Mr Cameron will tell security experts: “The cause is ideological. It is an Islamist extremist ideology one that says the West is bad and democracy is wrong that women are inferior and homosexuality is evil. It says religious doctrine trumps the rule of law and Caliphate trumps nation state and it justifies violence in asserting itself and achieving its aims. The question is: how do people arrive at this worldview?

“I am clear that one of the reasons is that there are people who hold some of these views who don’t go as far as advocating violence, but do buy into some of these prejudices giving the extreme Islamist narrative weight and telling fellow Muslims: ‘you are part of this’.

“This paves the way for young people to turn simmering prejudice into murderous intent, to go from listening to firebrand preachers online to boarding a plane to Istanbul and travelling onward to join the jihadis.”

Mr Cameron will argue that Isis might be medieval in its outlook, but is modern in its tactics with the internet as its main tool to “spread its warped worldview”.

The Prime Minister will say Britain is strengthening its ability to “root out this poison” by giving the security services extra powers to thwart plots and working with internet providers to remove jihadi websites.

“We are doing these things because we acknowledge just how widespread, how complex and how dangerous this threat is,” he will say.