LONDON -- Prime Minister Tony Blair's government yesterday proposed sweeping new powers to tackle terrorism, including electronic tagging, curfews, and house arrest for terror suspects without trial.
The measures provoked swift dissent from civil libertarians and opposition politicians.
Home Secretary Charles Clarke said the new ''control orders" would apply to both foreigners and British nationals, and he promised to introduce legislation as soon as possible.
Eleven foreign terrorist suspects who have been held for three years without charge would not be released until the new powers were in place, he added.
''There remains a public emergency threatening the life of the nation," Clarke told the House of Commons. ''The threat is real, and I believe that the steps I am announcing today will enable us more effectively to meet that threat."
Many Britons disagreed, however, expressing fears that extending the government's power would upset the balance between individual rights and the need for security.
The British government tried internment, locking people up without trial, in Northern Ireland, but abandoned that as a failure.
''I am very well aware that the proposals . . . represent a very substantial increase in the executive powers of the state in relation to British citizens who we fear are preparing terrorist activities and against whom we cannot proceed in open court," Clarke told lawmakers. ''This will be contentious, but I believe the need for us to protect ourselves against the threat justifies the changes I propose," he added.
Clarke said the government preferred to try terrorist suspects in court. But he said in some cases prosecution was impossible ''given the need to protect highly sensitive sources and techniques."
Instead, the new restrictions could be imposed if there were ''reasonable grounds" for suspecting terrorist activity, a lower standard of proof than is required in trials.
Measures would include bans on meeting certain people, restricting access to telecommunications including the Internet, curfews, and electronic tagging.
The proposal also included a new power to place suspects under house arrest without charge or trial.
But Clarke argued that telephone taps should continue to be excluded as evidence, because they may compromise the work of intelligence agencies.
A government review of the issue had found that ''evidential use of intercept would be likely to help secure a modest increase in convictions of some serious criminals but not terrorists," Clarke said in a written statement.
International investigations in the European Union are often hampered by differences in national legislation. Laws on phone tapping differ among the 25 EU nations; legal systems in EU states also are not uniform.
Blair's official spokesman denied a suggestion that the new measures were designed to deal with the four Britons who returned home Tuesday from the US Naval Base at Guantanamo Bay. They had been arrested on their return, but were released without charge last night.
The spokesman said Clarke was responding to a ruling last month by Britain's highest court that it was illegal to indefinitely detain without charge 11 foreign terrorist suspects.
The men, from Algeria, Tunisia, Egypt, and Jordan, have been held for three years under antiterrorism legislation rushed through Parliament shortly after the Sept. 11, 2001, attacks.
The House of Lords ruled that indefinite detention was incompatible with the European Convention on Human Rights and said the law was discriminatory because it only applied to foreigners. Clarke said the government accepted that ruling.
While the Muslim Council of Britain welcomed the announcement, as it heralded the eventual release of the 11 detainees from Britain's ''own mini Guantanamo Bay," others feared the sweeping new powers the government would hold over British citizens.
''The government wants draconian new powers," said the group Human Rights Watch. ''House arrest on the say-so of the home secretary has no place in a democracy."
The Law Society, the professional body for solicitors, said tagging and monitoring might be appropriate in some cases.
''If there is surveillance evidence, no matter how it has been obtained, it should be admissible in court," said Edward Nally, the society's president.
The opposition Conservative Party said the proposals could backfire. ''Unless the process is clearly just, the home secretary could find himself confining one known terrorist only to recruit for our enemies 10 unknown terrorists," said David Davis, a Conservative spokesman.