David Cameron is to warn that the "stakes are rising" in the battle against extremism as he unveils measures to prevent young people being radicalised.
The Prime Minister will insist the Government cannot turn a "blind eye" to the spread of terrorist ideologies as he launches a new counter-extremism strategy.
The plan will see an extension of powers for passports to be withdrawn from young people at risk of travelling abroad to join groups such as Islamic State (IS).
The mechanism has already been used on several under-16s since it was introduced in July, according to Downing Street, and will now be available for 16- and 17-year-olds.
There will be bans on radical preachers posting material online, and internet firms will work more closely with police to stop extremist material being disseminated.
Anyone with a conviction or civil order for terrorist or extremist activity will also be automatically barred from working with children and vulnerable people.
Mr Cameron, who yesterday announced that an extra £5 million will be ploughed into moderate muslim groups and charities this year, is to reiterate his view that defeating Islamist extremism is the "struggle of our generation".
"It is one of the biggest social problems we need to overcome," he will say.
"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?
"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.
"And a key part of this new approach is going further to protect children and vulnerable people from the risk of radicalisation by empowering parents and public institutions with all the advice, tools and practical support they need."
It is thought Mr Cameron will pledge to act on a review of sharia courts, and declare that all new arrivals to the country should respect "British values".
In a foreword to the strategy, Home Secretary Theresa May apparently defines these as "democracy, free speech, mutual respect and opportunity for all".
Shadow home secretary Andy Burnham said: "This is the greatest challenge of our age and the Prime Minister is right to devote his focus to it.
"For our part, we will always support measures that are reasonable, proportionate and evidence-based. But we have a job to ensure that, in this difficult area, the Government gets the balance right doesn't go beyond that.
"This summer, David Cameron failed to strike that balance by implying that the whole Muslim community 'quietly condones' extremism.
"He should use today's speech to correct that suggestion and set the right context for the difficult decisions that lie ahead by building bridges with the Muslim community.
"As David Davis warns, the PM needs to take care to make sure the measures are not heavy-handed. If he's not careful, they could have the opposite effect and fuel resentment, division and a sense of victimisation.
"The Government must proceed with the utmost caution and Labour will watch carefully to ensure the correct balance is achieved."