A judge has given the police seven more days to question the 11 men suspected of links with the al-Qaeda and detained in raids across northwestern England on Wednesday,the police said on Saturday.
The twelfth suspect,an 18-year-old,has been released without charge into the custody of the UK Borders Agency,which regulated immigration and investigates the status of those entering the country. Any decision to deport him lies with the Borders Agency,a police spokesperson said.
The police,meanwhile,are continuing to search 10 addresses in Liverpool and the Cheetham Hill area of Greater Manchester.
Intelligence reports that led Britains security and counter-terrorism officers to believe that a terrorist cell was planning to launch a large scale attack on the British soil came from M16,Britains foreign intelligence agency,a report in the Guardian stated on Saturday.
A source was quoted by the Guardian as saying that nothing of huge significance had been found,and accepted that it was possible no evidence could emerge before the 28-day limit to hold the suspects.
A few weeks ago,intelligence operations carried out in Pakistan by M16 provided the names of suspected members of an al-Qaeda network in Britain.
British authorities believed that the foiled terror attack in the country was al-Qaeda driven and that a link existed between suspected al-Qaeda commanders in Pakistan and the suspects held in the UK.
Interception of calls and e-mails of suspects in the UK terror plot had led British security officials and police to fear that a large terrorist strike was in the offing.
However,investigators say the operation is still at an early stage.
Examination of computers recovered from the raids in Manchester,Liverpool and Clitheros and their hard drives has only just begun.
There is a lot of material that may take us somewhere, Guardian quoted officials as saying,claiming that it will be a long and drawn out investigation.
The operation has caused a diplomatic spat between Britain and Pakistan,with Brown calling on Pakistan to do more to root out the terrorist elements in its country.
Pakistans top diplomat in Britain,Wajid Shamsul Hasan,said on Friday Pakistani authorities could help carry out background checks on student visa applicants but had not been allowed to.