Britain's top counter-terrorism chief is under mounting pressure to quit after a security blunder forced police to launch a massive anti-terror operation.
Searches are continuing at addresses in the North West after hundreds of officers carried out raids on 10 properties, arresting 12 men - including 10 Pakistani nationals on student visas and one Briton.
Sources said the raids were brought forward after Assistant Commissioner Bob Quick was pictured in Downing Street clutching sensitive documents.
Fearing the suspects would be tipped off about the planned operation - codenamed Operation Pathway - police swooped at about 5.30pm on Wednesday on addresses in Cheetham Hill, Manchester, Liverpool - including John Moores University - and Clitheroe, in Lancashire.
A brand new Homebase DIY store was also raided by more than 100 officers. Two staff members are believed to have been arrested.
As police targeted the suspects - who sources claim could be linked to al Qaida - Mr Quick released an apology to Met Commissioner Sir Paul Stephenson saying he "deeply regretted" leaving the document on show.
Shadow home secretary Chris Grayling said: "This is an extraordinary and very alarming lapse.
"It's the kind of error that Britain's most senior anti-terrorist officer simply can't afford to make, and it will lead to serious questions about his judgment and about his ability to do his job properly."
Daniel Taylor, a journalism student at John Moores, gave an account of one of the police raids. He said: "I was on the second floor of the library when I heard a lot of shouting outside.
"When I looked I saw a man on the floor. Police were shouting at him and one of the officers had what looked like a machine gun pointed right into his head."
