Human rights groups have branded new terror laws going through parliament this week as "a recipe for injustice".
Shami Chakrabarti, director of Liberty, said: "Yet again politicians resort to high talk and rushed legislation in an attempt to look tough in the face of terrorism.
"So youngsters will have their passports seized at borders and others will be prevented coming home. Even our universities must read from ministers' scripts on radicalisation.
"Another chilling recipe for injustice and resentment by closing down the open society you seek to promote."
Emma Carr, director of Big Brother Watch, added Theresa May's speech had "highlighted that the 'snoopers' charter' was anything but dead and buried."
Dr Steve Hewitt, from the University of Birmingham, says there isn't much more the government can do to tackle terrorism.
The terror threat posed by violent extremists has "evolved", one of the UK's most senior counter-terrorism officers has warned.