UK raises terror threat level
London - Britain raised its terror threat level from substantial to severe on Friday, suggesting that an attack is "highly likely", Home Secretary Alan Johnson said.
"The Joint Terrorism Analysis Centre has today raised the threat to the UK from international terrorism from substantial to severe," Johnson said.
"This means that a terrorist attack is highly likely, but I should stress that there is no intelligence to suggest than an attack is imminent."
In a television statement shortly afterwards, Johnson refused to say whether the change in the threat level, which takes it to the fourth highest level out of five, was linked to the failed Detroit plane bombing on December 25.
"We never say what the intelligence is and it would be pretty daft of us to do that," he said, adding: "It shouldn't be thought to be linked to Detroit or anywhere else for that matter."
He said: "The appraisal centre looks at all factors and no one should draw any assumptions from this."
State of vigilance
The increased threat level meant that Britain would put "more resources in, we heighten the state of vigilance", he added.
In a statement issued by his office, Johnson insisted the threat level, which has been made public on the website of the domestic security agency MI5 since August 2006, was kept "under constant review".
The terrorism analysis centre "makes its judgments based on a broad range of factors, including the intent and capabilities of international terrorist groups in the UK and overseas", he added.
Johnson said Britain continues to face a "real and serious threat" from international terrorism and urged the public to remain vigilant and report any suspicious activities to the authorities.
The threat level was last at severe on July 20 2009, when it was downgraded to 'substantial' which means the threat of a attack is a "strong possibility".