Only one in four people arrested in Britain on suspicion of terrorism in the last year was charged with a terror-related offence, figures show.
The number of terror-related arrests also fell 35% from 201 in the previous 12 months, the Home Office said.
Some 130 people were arrested in the year to September 2010, and 36 charged with terror-related offences.
A total of 22 of the arrests led to non-terrorism-related charges but 59 people were freed without charge.
The Home Office figures showed that more than three in five of the suspects were dealt with within 48 hours and none of the suspects were held for more than 14 days in pre-charge detention.
The coalition recently allowed the ability to hold terror suspects for 28-days to lapse by not putting an annual renewal vote to Parliament and the system has reverted to a maximum of 14 days detention before a charge has to be brought.
The data also shows that a total of 1,897 terrorism arrests have been made since the the 11 September terror attacks in the US 2001, with 420 charged with terrorism-related offences and 240 convicted.
Of the others, 32 were still awaiting prosecution at the end of December.
Twenty prisoners convicted of terrorism-related offences were released between April and September last year, including four who had served four years or more behind bars.
On 30 September 2010, a further 111 were in prison in Britain for extremism or terror-related offences, with 22 classed as domestic extremists or separatists.
Separate figures are published for terror-related arrests in Northern Ireland.