London : Britain was facing the risk of an imminent terrorism attack for the third day Monday following attempted car bombs in London and at Glasgow airport in Scotland.
Police were reported to be urgently hunting at least one more suspect involved in failed car bombings, after so far arresting five people, which the media leaks reported were all foreign nationals.
The official terror alert was raised to 'critical,' the highest level, after a Jeep Cherokee, loaded with gas cylinders, crashed into the main terminal building at Glasgow airport on Saturday.
It came after two car bombs were found in central London on Friday.
Home Secretary Jacqui Smith defended the decision not to raise the terror alert level earlier in the light of suggestions that the Prime Minister Gordon Brown's government could be a target.
The decision on the level was taken by an independent committee and the UK is taking action against a "serious and sustained threat from al Qaeda-related terrorism," said Smith.
She added there is a need for a "renewed effort" to involve communities, including Muslims, in tackling terrorism.
"I want to work with David Miliband at the Foreign Office and with Hazel Blears at the Department of Communities and Local Government (to see) what we can do to make sure that we're tackling the type of perverted ideology that is related to this terrorism," Smith said.
In his last broadcast interview before his resignation, former Prime Minister Tony Blair warned that Britain faces a continuing threat from international terrorism.
"This is what my successor and his successor will face and probably the successor after that too," the former premier said in the interview to be screened by the Channel Four of Britain on Monday night.