British police denied making an embarrassing mistake despite releasing all 12 men seized in raids to foil a suspected al Qaeda plot that were brought forward due to a security breach.
The men, 11 Pakistanis and one Briton, were arrested in northwest 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 Chief Constable Peter Fahy said on Wednesday that police had carried out their duty and their actions were not a mistake.
The raids were mounted several hours ahead of schedule after a blunder by Britain's top counter-terrorism officer Bob Quick.
He resigned after a document on the operation was photographed as he carried it to a briefing for Brown.
Mr Fahy said the mistake had not compromised the operation.