LONDON (Reuters) - Britain has arrested more than 1,400 people under anti-terrorism laws since September 11, 2001, the government said on Wednesday, but only a third of those were charged and even fewer convicted.
Releasing the first complete statistics on the issue, covering the period from the attacks on the United States to March 31, 2008, the Home Office said there had been 1,471 arrests under the Terrorism Act.
Of those, 521 (35 percent) resulted in charges being brought, of whom 102 (7 percent of the arrests) were ultimately convicted under terrorism legislation. A further 94 were convicted under non-terrorism legislation.
The statistics do not, however, include those who are charged and awaiting trial, or those who have been convicted of a terrorism-related crime since March 2008.
Britain has been on high alert over terrorism since September 2001 and especially since four suicide bombers blew themselves up on the London transport network in July 2005, killing 52 commuters. Other planned attacks have been foiled.
It has introduced progressively more stringent anti-terrorism laws, allowing suspects to be detained for up to 28 days without charge, and stop and search operations on the streets.
The 28-day detention rule make Britain one of the strictest countries in Europe when it comes to holding suspects.
Human rights groups are opposed to the measure, but the government insists it is necessary and failed in a recent bid to increase it to 42 days.
According to the figures released on Wednesday, only six people have been held for the full complement of 28 days without charge. Three were ultimately charged.
Paul Wiles, chief scientific adviser at the Home Office, said the proportion of terrorism suspects arrested who were later charged was similar to the rate for other criminal offences, at around 35 percent.
A recent trial of three men who prosecutors said were involved in planning the July 2005 attacks failed to reach guilty verdicts on those charges, but two were convicted of lesser terrorism offences.
Wiles said the figures would be updated every quarter in the future.
"The main offences for which suspects were charged under terrorism legislation were possession of an article for terrorist purposes, membership of a proscribed organization, and fundraising, all offences under the Terrorism Act," he said.
The figures showed that 117 people are currently serving prison sentences in England and Wales for terrorism or terrorism-related convictions. Of those, 62 percent were UK nationals and 91 percent classified themselves as Muslims.
Reporting by Luke Baker; editing by Steve Addison