London (AFP) - Britain on Wednesday unveiled draft legislation to ban extremist preachers from universities, increase surveillance on suspected radicals and stem the flow of jihadists joining the Islamic State group.
The Counter-Terrorism and Security Bill has already come under criticism from Muslim rights campaigners and civil liberties groups who have raised concern about measures not subject to review by the courts.
"We are in the middle of a generational struggle against a deadly terrorist ideology," Britain's interior minister, Theresa May, said.
"In an open and free society, we can never entirely eliminate the threat from terrorism.
"But we must do everything possible in line with our shared values to reduce the risks," she said.
- 'Dumping suspect citizens' -
One of the most contested proposals is a ban for Britons suspected of fighting in Iraq and Syria from re-entering the country for up to two years unless they agree to be subjected to strict monitoring.
Critics have said these "temporary exclusion orders" come close to making British citizens "stateless", a breach of international law that could also create a headache for transit states like Turkey.
Police will also have the power to seize passports and travel documents of people thought to be going abroad to engage in terrorism and relocate terror suspects to different parts of the country.
David Anderson, the independent reviewer of anti-terror legislation, criticised the plans.
"Where are the courts?" he asked at a parliamentary committee on human rights, adding that there may be a "more sensible" way of dealing with those suspected of terrorist activity.
"The role of the courts... is important if you don't want these laws being abused," said Simon Palombi, a consultant for the international security department at the Chatham House think tank.
Palombi said the "most controversial" measure was obliging Internet service providers to hand over data on Internet Protocol (IP) addresses to trace individual smartphone and computer users.
Making schools and universities legally liable for helping to deter radicalisation was also "a very slippery slope", he warned.
"I think you are going to find a lot of opposition there," he said.
Shami Chakrabarti, director of rights group Liberty, strongly criticised plans to curb suspected radicals returning to or leaving Britain.
- 'Dangerous to rush' -
"Dumping suspect citizens like toxic waste, abdicating your responsibilities to the international community, is a very strange way of promoting the rule of law," she said.
"Summary powers to 'stop and seize' passports at airports will prove just as divisive and counterproductive as the infamous 'stop and search' powers that preceded them."
The government says the changes are necessary to deal with mounting threats from the Islamic State group and other militant groups, including Boko Haram, Al-Shebab and Al-Qaeda in the Arab Peninsula.
Among the measures is also a ban on British insurers refunding clients who pay out kidnap ransoms when there is a suspicion that the money will end up financing militant groups.
The changes come after Britain raised its threat level from "substantial" to "severe" and as more than 500 Britons are believed to have gone to Iraq and Syria to fight in the IS group's ranks.
In the latest development, police on Wednesday said they had arrested a couple at Heathrow Airport for "Syria-related terrorism offences" after they got off a flight from Istanbul.
The government has repeatedly warned that the return of war-trained jihadists presents an immediate risk to Britain, although critics say the measures are more about next May's general election.
Human rights watchdog Amnesty International's legal advisor Rachel Logan warned it was "dangerous to rush through this grab-bag of measures without proper scrutiny or challenge".
May earlier this week said that police had foiled 40 attacks in the last nine years, including a Mumbai-style gun attack and a planned murder of armed forces personnel and tougher laws are needed.
But advocacy groups from Britain's 2.8-million strong Muslim community say the measures will further marginalise ordinary believers.
Cerie Bullivant, a spokesman for the Cage group, said the legislation "further leads to young people not feeling that they're included in society, not feeling that they have the same rights as the rest of society, which only makes radicalisation more likely not less".