All 12 suspects arrested in a security operation to thwart what the Prime Minister called “a very big terrorist plot” have been released without charge.

Eleven of the men - all Pakistani nationals - face being deported after they were transferred into the custody of the UK Borders Agency.

The failure to bring charges against any of the men came after police released the final two suspects they had in custody this morning.

Last night they freed nine men, aged between 22 and 38, after 13 days detention. An 18-year-old student was transferred to the custody of the UK Border Agency after three days in detention.

Mohammed Ayub, a lawyer for three of the men, called for an independent inquiry into Operation Pathway and said their deportation orders would be challenged.

“Our clients have no criminal history, they were here lawfully on student visas and all were pursuing their studies and working part-time,” he said.

“They are neither extremists nor terrorists. Their arrest and detention has been a serious breach of their human rights. As a minimum they are entitled to an unreserved apology.”

Responding to criticism of the police operation, Gordon Brown’s spokesman said: “Both the Home Secretary and the Prime Minister believe they are doing an excellent job in continuing to protect the public from terrorist threats.

"The Government’s highest priority is to protect public safety. Where a foreign national poses a threat to the country, we will seek to exclude or deport them where appropriate.”

The investigation into alleged al-Qaeda activity in the North West involved 14 properties in Manchester, Liverpool and Clitheroe, Lancashire, being searched by specialist teams.

Four uniformed police officers stood guard outside 36, Galsworthy Avenue, in Cheetham Hill where two of the terror suspects were arrested in an armed swoop two weeks ago.

The sunlit street was deserted apart from a few pressmen and one passer-by who shouted aggressively: "Go home - it all over now."

Times Recommends

• Times Christmas appeal: Letter from the Editor
• Conferences — what a waste of money
• Schools supremo learns a painful lesson