Police today denied making an embarrassing mistake after releasing all 12 men seized in raids to foil a suspected al-Qa'ida plot that were brought forward due to a security breach.
The 11 Pakistanis and one Briton were arrested around north-west England on 8 April as part of an operation against what Prime Minister Gordon Brown called at the time a "very big terrorist plot."
Police said all the suspects had been released although 11 had been handed over to immigration officials and face deportation on national security grounds.
Prosecutors said there was insufficient evidence to justify holding them any longer or bringing charges, Greater Manchester Police (GMP) said.
"This is not a mistake. I do not feel embarrassed or humiliated by what we have done because we have carried out our duty," GMP Chief Constable Peter Fahy told reporters.
"We do not carry out this sort of operation or make these sorts of arrests on a wing or a prayer or a whim. We can only operate to one standard, and that standard is that people are innocent until they are proved guilty."
The raids were mounted several hours ahead of schedule after a blunder by Britain's top counter-terrorism officer Bob Quick.
A document on the operation was photographed by journalists as Quick carried it to a briefing for Brown. Quick resigned a day later but Fahy said the mistake had not compromised the operation.
Police have been on high alert since the 11 September, 2001 attacks on the United States and especially after four young British Islamists carried out suicide bombings on London's transport network in July 2005, killing 52 people.
Dozens have been convicted of plotting bombings since 2001 and currently 68 people are on trial or awaiting trial for terrorism offences, said Fahy.
However, it is not the first time that suspects have been freed after claims that a major terrorism plot had been foiled.
In 2004, GMP arrested 10 people in raids involving some 400 officers amid media speculation of a plot to blow up Manchester United's Old Trafford stadium during a high-profile game.
They were all freed without charge.
The most notorious case occurred in 2006 when officers, some wearing chemical, biological and radiological protection suits stormed a house in east London looking for a suspected bomb, and shot one of the occupants.
No bomb was found and police later admitted their intelligence had been faulty.
"When we look at the record of the anti-terrorist police across the whole country but especially Scotland Yard, their record is actually very, very good," said security consultant Peter Ryan, a former national director of UK police training.
The Muslim Council of Britain said arrests were understandable but criticised Brown, who had also angered Pakistani officials by calling on Pakistan to do more to "root out the terrorist elements in its country."
"We would hope that senior ministers and the Prime Minister will understand that it is completely unfair to make prejudicial and premature remarks in cases like this," said spokesman Inayat Bunglawala.
He added the decision to deport the men following their release was "very dishonourable."
Mohammed Ayub, a defence lawyer for some of the suspects, said: "This seriously damaged police credibility. The arrests happened in a blaze of publicity but finally amount to nothing."Reuse content