British Prime Minister David Cameron will launch a new strategy Monday aimed at countering extremist ideology and stopping young Britons travelling to Syria.

British Prime Minister David Cameron will launch a new strategy Monday aimed at countering extremist ideology and stopping young Britons travelling to Syria.

Key measures in the plan include allowing parents to have passports removed from 16 and 17-year-olds, and barring those with terrorism or extremist convictions from working with children and vulnerable people.

"We know that extremism is really a symptom; ideology is the root cause -- but the stakes are rising and that demands a new approach. So we have a choice -- do we choose to turn a blind eye or do we choose to get out there and make the case for our British values," Cameron is expected to say later on Monday according to released remarks.

"The government's new counter-extremism strategy is a clear signal of the choice we have made to take on this poisonous ideology with resolve, determination and the goal of building a greater Britain."

Police say they have foiled several attacks in Britain, while hundreds of Britons are believed to have travelled to Syria and Iraq to join the Takfiri group, ISIL (so-called Islamic State in Iraq and Levant), raising concerns that not enough is being done to counter extremism.

A 15-year old boy, thought to be Britain's youngest person convicted of terrorism, was sentenced earlier this month to a minimum of five years in jail for plotting an ISIL-inspired "massacre" on an Anzac Day parade in Australia.

Cameron is expected to describe extremism as one of Britain's biggest social problems and "the struggle of our generation".

Citing police figures, Cameron's Downing Street office said there were 338 counter-terrorism related arrests in the past year, with 157 linked to Syria and 56 involving suspects under 20.