As part of changes to anti-terror laws in the UK, Home Secretary Charles Clarke has proposed strict powers of house arrest for people suspected of terrorism activities. Opposition parties have criticised the proposals as excessive and authoritarian.
The BBC News website asked six commentators for their views on what is proposed - before the latest details emerged about government amendments to the bill.
Ken Jones, Association of Chief Police Officers and Chief Constable of Sussex Police
The police service welcomes, and strongly supports, the announcement made by the Home Secretary.
The constantly evolving nature of the threat posed to this country by international terrorism demands that those charged with countering that threat have the tools they need to do the job.
It is inevitable that terrorists will attempt to attack the United Kingdom. It is not inevitable that they will succeed. The proposals will assist the country's security agencies, and the police service, to better contain the terrorist threat.
The police service supports the introduction of effective measures which are designed to counter the real and significant international terrorist threat we face. These are extraordinary times which call for the introduction of extraordinary measures.
The consequences of a successful attack within the United Kingdom of the kind seen recently in other countries are profound. We need to intervene and disrupt, at a very early stage, those who are intent on terrorist activity in the UK.
Patrick Mercer MP, Conservative Party shadow spokesman for homeland security
It is quite wrong that in conditions short of all-out war, we should impose these sorts of powers.
A judge should make the decision as to whether someone's liberty should be taken, not a politician.
We have given the government a model whereby a vetted judge can look at intelligence and intercept evidence before it is heard in an open court, with a view to bringing suspects to trial.
It is entirely unacceptable that suspects should be held indefinitely without charge and many of the control measures that the government is talking about are both unprecedented and impractical.
The government talks about the need for this law being in place before a general election. They are clearly worried about terrorist attacks during the election period. But they also talk about laws deterring terrorists.
Words and paper will not deter suicide bombers. Where are the practical measures that will physically secure the population against attack?
Shami Chakrabarti, director of Liberty, human rights organisation
In the wake of the twin towers atrocity in New York, the government passed emergency legislation permitting the indefinite detention without charge or trial of foreign nationals suspected of terrorism.
The government sidestepped all of the ancient fair trial protections which distinguish our great democracy from dictatorships throughout the world.
Over three years on, the detainees have never seen the "secret intelligence" case against them. The government admits that some of the material may have been gained by torture abroad.
Detainees have never been charged with a criminal offence or even been interviewed by a police officer. Britain's highest court condemned this terrifying law as "the stuff of nightmares".
The government's response is to push legislation for "control orders" through Parliament in less than two weeks.
This new law will also apply to British nationals and will allow for house arrest, curfews, electronic tagging and many other punishments on the basis of closed secret intelligence rather than a trial.
Some politicians are trying to sugarcoat the unpalatable by calling for judges rather than politicians to issue "control orders".
This will not help you if you had no knowledge of the accusation or evidence against you. And so the nightmare continues.
Mark Oaten MP, Liberal Democrat spokesman for Home Affairs
The Liberal Democrats recognise the importance of balancing the security of the nation with strong principles of justice. We do not underestimate the terror threat facing Britain, and want to make sure that when responding we put the right measures in place.
We welcome Charles Clarke's shift toward strengthening judicial review of the powers outlined in the Prevention of Terrorism Bill.
But we remain firm in the belief that it must be a judge, not the Home Secretary, who takes the initial decision on any control order.
Judicial involvement is an important start but it's only the first step. We want to see the Home Secretary make his case to the highest possible standard of proof, in as open a court as possible, where the defendant has knowledge of and opportunity to dispute the evidence against them.
Further concessions on these issues are the only way we can guarantee a balance between civil liberties and the need to protect our country.
As responsible politicians, we have entered into negotiations with the Government in good faith, but they have a very long way to go before we could even consider offering our support.
Professor Paul Wilkinson, chairman of the Centre for the Study of Terrorism and Political Violence at St Andrews University
I have no doubt that the government is correct in warning that there is a serious threat of terrorist attack from the Al-Qaeda network or one of its affiliates.
However, in my view the government's proposed new anti-terrorism measure of house arrest without trial for terrorist suspects, no doubt intended to protect national security, would not only involve derogation from Article 5 of the European Convention on Human Rights, it would also be dangerously counter-productive.
The government's argument is that they cannot resort to the courts because they do not have sufficient evidence which can be used in court.
Other democratic governments have dealt effectively with this problem by ensuring that their courts have the means to try such cases properly, for example by allowing intercepts to be used as evidence in court, by appointing special judges cleared to hear evidence pertaining to national security.
Why is the UK unable to strengthen its judicial process by such means?
I would also argue there are major security problems involved. House arrest without trial and other draconian measures would become a recruiting sergeant for terrorist organisations.
The private residences of suspects would become magnets for protests and demonstrations by supporters/sympathisers of the suspects, potentially leading to violent public order confrontations with our already overstretched police, and possibly leading to the escape of the suspects.
It is dangerous to rush through a change in the law which undermines such a fundamental civil liberty. Think what an authoritarian government might do with such a power
Andy Burnham, Labour Party MP and former parliamentary private secretary to David Blunkett
Most, if not all, the Labour MPs I know did not get into politics because of a desire to pass tough legislation of this kind.
But there is an acceptance that any government must first and foremost protect its citizens; it is only by fulfilling that primary duty do we earn the right to implement the progressive policies that lift Labour hearts.
It is just possible that the government's anti-terrorism measures have become a victim of their own success. Three and a half years have passed since 11 September 2001 and we have not seen that "inevitable" attack.
So the policy context has changed, helped perhaps by the legislation that was introduced, and the climate in which the debate is being conducted is very different from those fevered and anxious days at the back end of 2001.
But it would be a grave mistake to assume that this means the threat from global terrorism has diminished. Al-Qaeda plays a long game. Spain was a long-standing target not for just for recent actions but its 15th century campaign against the Moors.
So I voted to support the principle of home detention for terror suspects. There are some people in the UK whose activities in other countries mean they simply cannot be allowed to walk freely through our streets.
But I accept there is a legitimate debate to be had about the extent to which the control order process is political or judicial.
In my view, the elected home secretary is charged with safeguarding our security. If things go wrong, he will carry the can.
It is reasonable that he should have the power to act swiftly as long as his actions are subject to scrutiny.
We are in real danger of allowing an assumption to take root that decisions taken by a politician are by definition tainted in some way.
What is beyond doubt is that there is no excuse for political posturing on these vital issues in the run-up to the general election. Michael Howard may come to regret his latest bout of opportunism.