By IANS
London : The national terrorism threat level of Britain has been upgraded to "critical" following the discovery of two car bombs in London and a car bomb attack on Glasgow airport.
The three incidents have led to airport closures in Edinburgh, Newcastle and Blackpool. Other airports are likely to be closed following a review of security assessment of what is widely seen as the biggest threat Britain has faced since the July 2005 London bombings.
Four days in office as prime minister, Gordon Brown urged the public to be vigilant and added: "I know the British people will stand together, united and resolute."
Brown, his new Home Secretary Jacqui Smith and senior security officials held a series of meetings after a vehicle in flames crashed into the Glasgow airport's main terminal building Saturday afternoon. On Friday, two car bombs were found in central London.
In a televised statement, Brown thanked the police, the security and emergency services for the "dedicated professionalism" that has been shown in London and Glasgow airport.
"The first duty of the government is the security and safety of all British people, so it is right to raise the level of security at airports and in crowded places in the light of the heightened threat," he said.
Security has been upgraded for major public events such as the Concert for Diana at Wembley Stadium and the Wimbledon tennis championships.
Security officials believe that the discovery of 'Baghdad-style' car bombs may be linked to Al Qaeda but are concerned that no intelligence had been intercepted into any of the three attempted car bombings.
The attack on the Glasgow airport appeared to be aimed at killing passengers, set off on the first day of the Scottish school holidays. It was only foiled because the jeep hit protective bollards and got stuck in the terminal doors.
Robin Patterson, an eyewitness of the Glasgow attack, told The Observer: "It was just a small fire at first. Then there was an enormous explosion and it really was a big explosion.
"The guy next to the car, his skin and clothes just fell off him. He came running away from the car and he was like an absolute lunatic. He was just literally running away from the police."
Richard Gray, another eyewitness, said: "A green jeep was in the middle of the doorway burning. There was an Asian guy who was pulled out of the car by two police officers, who he was trying to fight off. They got him on the ground. The car didn't explode. There were a few bangs, which presumably was the petrol."