Prime Minister David Cameron said IS poses a "greater and deeper threat to our security than we have known before" claiming the UK must confront the terrorist group's ideology.
A "firm security response" using all the resources at the UK's disposal was needed to combat the threat, Mr Cameron said.
The Prime Minister warned that Britain was involved in a "generational struggle against a poisonous and extremist ideology" that it could be "fighting for years and probably decades".
"We cannot appease this ideology. We have to confront it at home and abroad," Mr Cameron said.
The PM wants to confiscate passports. But in Cardiff they want to solve extremism at it's roots - they just can't get the help to do it.
David Cameron has unveiled a series of new measures to combat the threat of terrorism.
Rumours suggesting London's Tube network will be targeted in a terrorist attack on Monday are "completely untrue", police say.