LONDON An Internet posting that proclaimed the creation of an al Qaeda branch in Britain is viewed by intelligence officials as typical militant "background noise", a security source said on Wednesday.
An unidentified individual posted the claim in Arabic on a password-protected militant forum on January 2, saying the new "al Qaeda in Britain" would carry out major attacks including on political leaders, naming Prime Minister Gordon Brown and his predecessor Tony Blair.
"We would assess it as an aspiration, rather than any one individual or group having the capability to do the things they are suggesting," said the security official, speaking on condition of anonymity.
"This is the stuff we get all the time, background noise ... In other circumstances you might regard this person as a bit of a fantasist," he told Reuters.
Britain has seen a marked increase in attacks by Islamist militants since it joined the United States in invading Afghanistan and Iraq in the wake of the September 11, 2001 attacks on New York and Washington.
In July 2005, Islamist suicide bombers killed 52 people in coordinated attacks on London's transport system. Several other alleged plots have failed or been uncovered by police, including attempted car bombings in London and Glasgow last June.
The new Internet posting appeared only briefly on www.alekhlaas.net, a site which hosts a catalogue of Islamist messages, musings and writings and has been visited by more than 17 million people.
The security official said the assessment did not mean Britain was complacent about the danger from al Qaeda, noting that the official threat level is judged as severe, meaning "an attack is highly likely".
MI5 spy chief Jonathan Evans said in November the agency knew of at least 2,000 British-based individuals who posed a direct threat to national security because of their support for terrorism. Children as young as 15 were being groomed to carry out attacks, he said.
(Reporting by Mark Trevelyan, Editing by David Clarke)