Police investigating an alleged plot to blow up several transatlantic planes have taken the unusual step of releasing a number of pieces of information into the public domain after suspects were charged.
Eleven people have been charged in connection with the alleged plot.
Police have so far made 69 searches of premises and vehicles
The Met's Deputy Assistant Commissioner Peter Clarke told journalists bomb-making equipment, including chemicals and electrical components had been found during the investigation into the alleged plot.
A number of video recordings known as "martyrdom videos" had also been recovered, he said.
BBC home affairs correspondent Daniel Sandford said the "highly unusual move" has been criticised by lawyers who say it is "wrong to rehearse the evidence before the public when there's going to be a trial".
The Contempt of Court Act stipulates that the amount of evidence revealed prior to a trial should be limited to ensure that the jury is not unfairly influenced.
John Cooper, a criminal barrister, said: "There is a risk that the police may have gone too far. Only time will tell. We will only really know when the trial starts, and that could be one or two years in the future.
"The problem is that since the police have introduced this at an early stage...it could well be evidence that is ruled inadmissible."
But other lawyers said the disclosures were unlikely to have an affect because jurors are likely to have forgotten the details by the time the suspects go on trial.
Daniel Sandford said: "There's a feeling at Scotland Yard that, such is the seriousness of the material that they've found and such is the seriousness of the measures that they took at airports, that they have to try to explain to the public why it is that they've done this."
Speaking after the charges were made, Mr Clarke said: "I would like to reassure the public that we are doing everything we can to keep you safe so that you can live your lives without being in constant fear.
"The threat from terrorism is real. It is here, it is deadly and it is enduring.
"As we all look for explanations, we cannot afford to be complacent and ignore the reality of what we face."
Mr Clarke said the investigation of the material seized by police was likely to take months.
He then went into significant detail about the police investigation so far and the evidence their inquiries had uncovered. This included:
69 searches carried out 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
Police experts have removed 6,000 gigabytes of data from the seized computers
Bomb-making equipment, including chemicals and electrical components have been seized, police said
A number of video recordings recovered.