The full text of statements by the Peter Clark, head of Scotland Yard's anti-terrorist branch, Home Secretary John Reid and Transport Secretary Douglas Alexander about the alleged terror plot disrupted by police.
PETER CLARK, SCOTLAND YARD'S ANTI-TERRORISM CHIEF
I would like to give you some details about the counter terrorist operation, which took place overnight.
I shall focus purely on the criminal investigation. As always, I must preface my remarks with a request for restraint - and by that I mean restraint in the reporting of events so far as they relate to those who have been arrested.
We must all, please, be careful to say or do nothing that might prejudice the right of any individual to a fair trial.
The investigation has focused on intelligence, which suggested that a plot was in existence to blow up transatlantic passenger aircraft, in flight.
The intelligence suggested that this was to be achieved by means of concealed explosive devices smuggled onto the aircraft in hand baggage.
All airports have been put under the restrictions
The intelligence suggested that the devices were to be constructed in the United Kingdom, and taken through British airports.
The number, destination and timing of the flights that might be attacked remain the subject of investigation.
This has been, and continues to be, a fast-moving investigation.
Today marks the culmination of one phase of what is a major operation that has already lasted several months, and will undoubtedly last long into the future.
During the investigation an unprecedented level of surveillance has been undertaken and our objective is to gather intelligence and evidence in support of the investigation.
We have been looking at meetings, movements, travel, spending and the aspirations of a large group of people.
This has involved close co-operation, not only between agencies and police forces in the United Kingdom, but also internationally. As is so often the case in these investigations, the alleged plot has global dimensions.
The investigation reached a critical point last night when the decision was made to take urgent action in order to disrupt what we believe was being planned. As always in these cases, the safety of the public was our overriding concern.
Throughout the night a significant number of arrests were made.
All the arrests were made on suspicion of the commission, preparation or instigation of Acts of terrorism under the Terrorism Act 2000.
The people arrested remain in custody in London, where officers will pursue the investigation from the Metropolitan Police Anti-Terrorist branch.
Searches are also under way at a number of business and residential premises in London and elsewhere. We anticipate that these will take some time to complete.
You will realise that this is a very early stage in what will be a meticulous, painstaking criminal investigation.
We will now be embarking on the next stage of the investigation, an investigation that will take us wherever the evidence leads.
As and when I am able to do so, I will give out information on the progress of the investigation. But please be aware that we will only release specific information when we are sure it is correct.
I am sure you will understand that at this very early stage it is not appropriate for me to answer questions. I will give you further information only when I am able and it is appropriate to do so.
At this point I must focus on the criminal investigation and any subsequent legal process, and refrain from speculation.
HOME SECRETARY JOHN REID
The police, working with the security service, MI5, have carried out a major counter-terror operation overnight to disrupt an alleged plot to bring down a number of aircraft through mid-flight explosions.
Had this plot been carried out the loss of life to innocent civilians would
have been on an unprecedented scale.
While the police are confident the main players have been accounted for, neither they or the Government are in any way complacent.
This is an ongoing and complex operation.
We all believe we have taken the necessary precautionary measures to protect the public, both by the actions we have taken and by the means of that threat level, for the time being at the highest possible level.
We think that the main players are in custody, but we should always err on the side of caution which is why the threat level is at its highest critical level.
In general terms a terrorist will wish to use evil methods against the rest.
Therefore there is a common cause in this country, among all people in this country whatever background or ethnic dimension, because the threat is common to us all.
Indeed internationally most of the people who have been massacred are Muslim, mostly men, women and children, and in places far from here.
TRANSPORT SECRETARY DOUGLAS ALEXANDER
The very reason that we have taken the security measures that I described early this morning was to secure flights from Britain's airports.
We have been determined to send a signal that notwithstanding the challenges that we do face, putting in place that new safety regime, that we will continue to operate the British airports with planes coming in and leaving the United Kingdom.
But we believe that the steps that we have taken are the basis on which people can feel secure when travelling to and from the United Kingdom.
The seriousness of the threat gave us no choice but to require these stringent measures to be implemented.