Britain's security services have been put on their second highest state of alert after warnings of possible plans by al Qaeda supporters, the BBC reported on today, but said there was no specific or imminent threat.
The BBC has reported that the increased state of alert was not linked to the state visit next week by US President George W. Bush.
Britain has been on high alert since the September 11th, 2001 attacks in the United States.
The internal status for the security services - including the police, army and MI5 - had now gone to "severe general" from "substantial", the BBC said.
It said the increased internal alert, which is normally kept secret, followed warnings about plans by supporters of Osama bin Laden's al Qaeda network, which was blamed for the September 11th attacks.
Britain's Home Office declined to comment on the BBC report, saying: "We would never discuss threat levels."
The police would also make no comment.