Eight of the suspects were charged with two offences each of conspiracy to commit murder and preparing acts of terrorism.

The eight were identified as Ahmed Abdullah Ali, Tanvir Hussain, Umar Islam, Arafat Waheed Khan, Assad Ali Sarwar, Adam Khatib, Ibrahim Savant and Waheed Aman.

One person, a 17-year old, was charged with possession of articles that could be used to prepare a terrorist act and two others were charged with failing to disclose information that could help prevent a terrorist act.

One woman has been released without charge, but the remaining 11 people are still being held while prosecutors decide whether to charge them.

Susan Hemming, the head of the Crown Prosecution Service Counter Terrorism Division, said: "We have been carefully examining and assessing the evidence against each individual with the assistance of anti-terrorist officers in order to come to charging decisions at the earliest practicable opportunity."

Bomb-making equipment

Police said that bomb-making equipment, including chemicals and electrical components, had been found during the investigation.

Peter Clarke, the head of the Metropolitan Police's anti-terrorism branch, said: "Since the 10th of August, we have found bomb-making equipment. There are chemicals, including hydrogen peroxide, electrical components, documents and other items.

"We have also found a number of video recordings - these are sometimes referred to as martyrdom videos," he said.

Hundreds of computers, mobile phones, DVDs and digital memory sticks have been seized in police searches at 69 locations including homes, businesses and cars.

Investigation continuing

"The investigation is far from over. The scale is immense," Clarke said. "The enormity of the alleged plot will be matched only by our determination to follow every lead and line of inquiry."

One suspect, 23-year-old Cossor Ali, the mother of an eight-month-old baby, was told she had been charged just before her lawyer was to lodge an application at the High Court challenging her detention, her lawyer said.

Twenty-five people in total have been arrested over the alleged plot, which police claim to have thwarted during a series of raids on August 10 which triggered unprecedented security measures at airports worldwide.

Two were subsequently freed without charge.