Since the 9/11 attacks hundreds of people have been arrested in the UK under anti-terror laws, but fewer than 20 have been convicted.
There have been complaints about detentions without charges
Between 11 September 2001 and 31 December 2004, were 701 arrests in the UK under the Terrorism Act.
But only 119 of these had faced charges under this legislation, with 45 of them also being charged for other offences.
A further 135 people were charged under
other legislation - including terrorist offences covered in other criminal law, such as the use of explosives.
Only 17 have been convicted of offences under the Act.
The details are contained in the Home Office's background briefing papers relating to the controversial Prevention of Terrorism Bill currently being considered by Parliament.
ARRESTS, CHARGES & DETENTION
701 arrested under Terrorism Act 2000
119 have been charged under it
17 have been convicted under the legislation
However, research by BBC Radio 4's Today programme suggests that not all those convicted under the Act were accused of participating in international terrorism.
Information gathered with the help of the Crown Prosecution Service (CPS) and Institute of Race Relations provided details of 13 convictions.
It emerged that three of the convictions related to Irish republicanism and four to the Irish loyalist movement.
Two stemmed from a Sikh terrorism case and one involved Tamil terrorism.
Only three related to some form of Islamic terrorism.
Civil liberties campaigners Liberty have referred to the detention of terror suspects without charge as Britain's "Guantanamo Bay" - and call it a "violation of human rights".
But the Home Office rejects this, saying that public safety is paramount and that the detentions are necessary.
The decisions to detain certain individuals were "made on the basis of detailed and compelling evidence", said a spokesperson.
Dr Paul Cornish, a security expert at King's College, London, says the heavy use of the Act, as well as Anti-terrorism Crime and Security Act 2001, reflects the sense of urgency to thwart an attack on Britain.
Those convicted under the Terrorism Act included Baghdad Meziane and Brahim Benmerzouga who were each jailed for 11 years after being found guilty in April 2003 of raising funds for terrorism.
In the same year two men were also jailed for belonging to a banned network, the International Sikh Youth Federation.
A further two people have been acquitted, including Sulayman Zain-ul-abidin who was cleared in 2003 of trying to recruit terrorists through a website he ran from his home in south London.
As its name suggests, the Terrorism Act 2000 actually pre-dates the attacks of 11 September 2001.
The legislation, which came into force in February of 2001, brought separate laws governing Britain and Northern Ireland under one roof.
It sets down a list of outlawed (in legal jargon "proscribed") terrorist organisations. These include al-Qaeda and several others such as the Kurdistan Workers' Party and the Tamil Tigers.
For some campaigners, the disparity between the number of people arrested and those who eventually face charges is worrying.
Charles Clarke's policies as home secretary have proved controversial
"There is clear evidence of disquiet in the Muslim community and a belief that they're being disproportionately targeted," said Barry Hugill of Liberty.
"When so many people are taken in for questioning and so few are convicted, it leads many to question the intelligence behind the raids."
Critics say the sweeping powers granted by the law, which lower the normal standards of reasonable suspicion, have been used to target Muslims in particular.
Community groups describe this as "racial profiling", for example considering somebody suspicious because of their style of dress.
But the law has been applied more widely. The trial of three men charged under the act with possessing guns and bomb-making devices to further the aims of the paramilitary Ulster Defence Association and Ulster Freedom Fighters, is due to start soon.
Yet to some, the fact that so many have been arrested then released without charge is evidence of a "fishing expedition" by the police.
There are fears that innocent Muslims will feel under suspicion
It has been reported that 230 of those initially held under the Act were accused of other offences, such as credit card fraud and immigration irregularities. The Home Office could not confirm this figure.
"In the US, post 11 September, the police used their extra powers to go rooting for wrong-doing. Now that's happening here," says civil liberties lawyer Louise Christian.
But a spokesman for the Home Office rejected the accusation, saying many held under the Act go on to be charged for terrorism-type offences.
"It's important to remember when looking at the statistics of people arrested under the Terrorism Act 2000 that they may be charged or convicted for related terrorism offences under other legislation such as making chemical weapons, murder or causing an explosion," said the spokesman.
"The Terrorism Act is not just about arrests and convictions. It contains many wider measures - such as the proscription of international terrorist organisations - which have an important deterrent and disruptive effect to prevent terrorists from operating in the first place."