The following is the full text of a statement by deputy assistant commissioner Peter Clarke, head of the Anti-Terrorist Branch, on developments following the bombings in London on Thursday July 7:
“As you are obviously all aware, we are conducting a complex and intensive terrorist investigation.
“I have to tell you this investigation is moving at great speed.
“The investigation quite early led us to have concerns about the movement andactivities of four men, three of whom came from the West Yorkshire area.
“We are trying to establish their movements in the run-up to last week’s attacks and specifically to establish if they all died in the explosions.
“Today we executed six warrants issued under the Terrorism Act at various premises in the West Yorkshire area.
“These included the home addresses of three of the four men to whom I have referred.
“A detailed forensic examination will now follow and this is likely to take some time to complete.
“We now know that all four of these men arrived in London by train on the morning of Thursday July 7.
“We have identified CCTV footage showing the four men at King’s Cross station shortly before 8.30am on that morning, July 7.
“One of the men who had set out from West Yorkshire was reported missing by his family to the Central Casualty Bureau shortly after 10 o’clock last Thursday, July 7.
“We have now been able to establish that he was joined on his journey to London by three other men.
“We have since found personal documents bearing the names of three of four of those men close to the seats of three of the explosions.
“As regards to the man who was reported missing, some of his property was found on the route 30 bus in Tavistock Square.
“Property in the name of a second man was found at the scene of the Aldgate bomb.
“And in relation to a third man, property in his name was found at the scene of both the Aldgate and Edgware Road bombs.
“We also have very strong forensic and other evidence that it is very likely one of the men from West Yorkshire died in the explosion at Aldgate.
“This of course is subject to formal confirmation by the coroner.
“The investigation is still in its early stages.
“As and when we find areas where the public can be of specific help we will of course give more information and ask for their help, which we know will be forthcoming.
“However, I would like at this stage to thank the public for all the support and assistance they have already provided. It is invaluable.
“At one of the searches in West Yorkshire some material has been found which has caused the West Yorkshire Police to take measures to ensure there is no risk to the public.
“The investigation of what has been found will be a detailed and lengthy exercise.
“At Luton a vehicle has been found in the station car park which we suspect is connected to this investigation.
“Again, steps are being taken to ensure that there is no risk to the public.
“One man has been arrested in West Yorkshire and will be brought to London tobe questioned.
“In this fast-moving and very complex situation it would not be appropriatefor me to answer questions about other aspects of the investigation.
“My absolute priority is the safety of the public and we will of course giveout further information as and when it is possible to do so in the future.’’