Eleven people appeared at a central London magistrate’s court on Tuesday charged with various offences relating to the alleged plot to explode transatlantic aircraft mid-flight. All had been held without charge since their arrest on August 10 in police raids in East London, Birmingham and Buckinghamshire.

Eight people have been charged with conspiracy to murder and the new offence, brought in under the 2006 Terrorism Act, of preparing acts of terrorism They include two recent converts to Islam, Umar Islam, 28, and Ibrahim Savant, 25, Tanvir Hussain, 25, Arafat Waheed Khan, 25, Ahmed Abdullah Ali, 25, and Waheed Zaman, 22. They were also charged with a second offence of preparing acts of terror and were remanded in custody until their next court appearance on September 4.

Assad Ali Sarwar, 26 (whose brother was wrongly reported to have been arrested with him), and Osman Adam Khatib, 19, were also remanded in custody until September 4, charged with conspiracy to commit murder and preparing acts of terrorism.

The other three have been charged with offences under the Terrorism Act of 2000.

Cossor Ali, 24, is charged with failing to disclose information “as soon as reasonably practicable” that she knew or believed may have been of “material assistance” in stopping another person carrying out a terrorist act. The mother of an eight-month-old baby, the charge against her is said to relate specifically to her husband Ahmed Abdullah Ali. An application for bail on her behalf was rejected.

Mehran Hussain, 23, has been charged with the same offence, but in connection to another person. Mehran Hussain and Cossor Ali have been remanded until September 19.

A 17-year old boy, who cannot be named for legal reasons, is charged with possessing articles useful to a person preparing acts of terrorism. He was remanded until September 29. Another woman was freed without charge.

In court, solicitors for the accused indicated that they would plead not guilty.

Eleven others continue to be held without charge. Police were last week granted an extension to continue questioning them until today. Under Britain’s draconian anti-terror laws, police can hold suspects without charge for up to 28 days.

In an unprecedented move, the charges were announced at a televised press conference held Monday and convened jointly by the Metropolitan Police and the Crown Prosecution Service (CPS) Counter Terrorism Division. No questions were allowed.

It is believed to be the first time that the CPS has made a statement pre-trial. Susan Hemming for the CPS outlined the charges against the 11 and said it was “extremely important that there should be responsible media reporting which should not prejudice the due process of law.”

Her reminder to the press made even more unusual the statement by Metropolitan Police Deputy Assistant Commissioner Peter Clarke, who followed directly after. Whilst Clarke avoided any reference to the specific charges, he spoke in some detail about the extent of the investigation, which has included 69 searches of houses, flats and business premises, vehicles and open spaces.

Searches “had found more than 400 computers, 200 mobile telephones and 8,000 computer media items such as memory sticks, CDs and DVDs,” he said, adding that police experts had recovered 6,000 gigabytes of data from the seized computers.

Police had also uncovered bomb-making equipment, including chemicals and electrical components, as well as a number of video recordings, which he called “martyrdom” tapes, saying they had “given us a clearer picture of the alleged plot.”

“The threat from terrorism is real. It is here, it is deadly and it is enduring,” he continued, warning that “the investigation is far from complete. The scale is immense, inquiries will span the globe. The enormity of the alleged plot will be matched only by our determination to follow every lead and line of inquiry.”

The press conference was particularly unexpected as police had been given until Wednesday to continue questioning many of those detained.

On Monday morning, it had been announced that solicitors acting for Cossar Ali were to challenge her continued detention at the High Court that afternoon, on the grounds that it was unlawful under the Human Rights Act because the district judge who had extended her detention almost one week ago had not explained his reasons for doing so. Her solicitor said it was when he arrived at court to argue this case that he discovered she was to be charged.

The police’s actions are undoubtedly driven by growing scepticism and numerous questions regarding the alleged plot. An opinion poll conducted for the Guardian newspaper over the weekend of August 12-13 found that 51 percent were convinced the government was not informing the public of the full story as to the alleged plot and 21 percent thought the government had “actively exaggerated” the danger.

Hemming’s joint presentation with Clarke, coupled with her statement that the CPS had “carefully examined and assessed the evidence” before deciding to proceed with charges, was intended to distance the latest terror scare from others which have turned out to be largely or wholly constructed through the actions of agent provocateurs.

But it will do nothing to quell demands for factual information to substantiate police and government claims that they had narrowly thwarted a terrorist atrocity on the scale of 9/11.

The charges themselves are very vague. Those against the eight, for example, state that between January 1, 2006 and August 10, 2006 the suspects “engaged in conduct to give effect to their intention to smuggle the component parts of improvised explosive devices on to aircraft and assemble and detonate them on board.”

The charge against the 17-year-old is that between October 1, 2005 and August 10, 2006 he possessed a bomb-making book, “some suicide notes and wills with the identities of the persons prepared to commit acts of terrorism and a map of Afghanistan containing information likely to be useful to a person committing or preparing an act of terrorism.”

The New York Times commented, “The nature of the charges raised new speculation about the scope of the plot, possibly suggesting that it was more limited than indicated by the sweep of the first arrests.”

The Times continued, “Mr. Clarke’s aim in offering such detail seemed two-fold: to give the impression that the police were offering the public a glimpse into the kind of evidence that was being amassed and to offset charges that the police had overreacted to a threat.”

Clarke has said that it “will take many months” to sift through all the material that has been accumulated over the last weeks. There are indications that it could be up to two years before those charged will stand trial and the evidence against them can be properly heard.