Britain today raised its security alert from "substantial" to "severe" level, implying that a terror attack in the country is "highly likely."
Home secretary Alan Johnson said the change is in response to the perceived increased threat from international terrorism following the failed Detroit airliner bombing on Christmas Day.
He, however, stressed that there was no intelligence to suggest a terrorist attack was imminent. The decision to raise the threat level was made by the UK's Joint Terrorism Analysis Centre (JTAC).
"We still face a real and serious threat to the UK from international terrorism, so I would urge the public to remain vigilant and carry on reporting suspicious events to the appropriate authorities and to support the police and security services in their continuing efforts to discover, track and disrupt terrorist activity," Johnson said.
"We never say what the intelligence is and it would be pretty daft of us to do that. It shouldn't be thought to be linked to Detroit or anywhere else for that matter," he added.
Lord Carlile, the government's independent reviewer of terrorism legislation, said the change was designed to make the public more aware, not to scare people.
