Prime Minister David Cameron will vow to tackle “failures of integration” when he unveils a five-year plan to combat home-grown Islamist extremism.
He will argue that the root causes of radicalisation must be tackled and say many people convicted of terrorism were influenced by non-violent extremists.
He will also promise action against the “glamorisation” of extremist groups such as so-called Islamic State.
It comes after he said the UK was committed to helping the US destroy IS.
In his speech in Birmingham later, the prime minister will say the country needs “to confront a tragic truth” that there are people born and raised in the UK “who don’t really identify with Britain and feel little or no attachment to other people here”.
“This is what we face: a radical ideology that is not just subversive, but can seem exciting, one that has often sucked people in from non-violence to violence, that is overpowering moderate voices within the debate and which can gain traction because of issues of identity and failures of integration.”
Mr Cameron will focus his message on convincing those tempted to travel to Syria and Iraq not to buy into the supposed “glamour” of fighting for IS.
“You won’t be some valued member of a movement. You are cannon fodder for them,” he will say.
“If you are a boy, they will brainwash you, strap bombs to your body and blow you up. If you are a girl, they will enslave and abuse you.”
He will also reject the idea that Western foreign policy is to blame for the rise in radicalisation and say any suggestion the government is attempting to spy on Muslims is “paranoia in the extreme”.
BBC political correspondent Chris Mason said he had been told the PM would set out what were described as “substantive new policies” on how the government would tackle potential radicalisation before it began.
He will also announce that he has appointed Louise Casey, director general of the government’s Troubled Families programme, to lead “a comprehensive review into boosting opportunity and integration to bring Britain together as one nation”.
Tracking Britain’s jihadists
The stories of those who have died, been convicted of offences relating to the Islamic State conflict or are still in Syria or Iraq.
The speech comes after Mr Cameron pledged a “full spectrum” response after 30 British tourists were killed by an IS gunman in Tunisia.
But he faced criticism for his comments. Former government minister and Conservative peer Baroness Warsi said the government lacked force as it had failed to help Muslims living in the UK, while Labour MP for Bolton South East Yasmin Qureshi said Muslims were tired of constantly being called on to apologise for the actions of extremists.
Police and security services believe at least 700 extremists have travelled to fight with IS militants who have taken control of large swathes of Iraq and Syria, with half since returned and posing a domestic terrorist threat.
Mr Cameron has suggested that he could soon seek parliament’s approval to extend UK military air strikes from Iraq into Syria, telling a US television network he wanted Britain to “step up and do more” to “destroy this caliphate”.