UK Threat level: CRITICAL

BBC News 24 eye witness:

"He was shouting 'Allah', throwing punches and shouting 'Allah'."

UK terror threat now 'critical'

The UK's national terrorism threat level has been raised to "critical" after attacks in Glasgow and London.

Prime Minister Gordon Brown urged the public to be vigilant and added: "I know the British people will stand together, united and resolute."

The announcement came after a meeting of the government emergencies committee Cobra, following a burning car being driven into a Glasgow airport terminal.

On Friday, two car bombs were found in central London.

Ministers, police and security service officials held their third meeting of Cobra in three days on Saturday evening, this time with a video link to ministers in Scotland.

In a televised statement, Mr 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 the 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.

The critical threat level indicates terrorist attacks are imminent. It is the highest possible level and was also in place after the 7 July 2005 suicide bomb attacks on London.

Security has also been tightened at airports across the US following the attempted attacks.

Strathclyde Police said the incident at Glasgow Airport was being treated as terror related and was being linked to the attempted bombings in London.

Two men were arrested at the scene at 1515 BST after the blazing car was driven into the airport's main terminal.

Chief Constable Willie Rae revealed one of the suspects who had been taken to the city's Royal Alexandra Hospital was in possession of "a suspect device".

Eyewitnesses described a Jeep Cherokee being driven at speed towards the main doors of Glasgow airport's terminal building with flames coming out from underneath shortly after 1500 BST.
Petrol and gas

All flights to and from the airport have been suspended.

A Scottish government spokesperson said Scottish Ministers were in touch with their Whitehall opposite numbers and First Minister Alex Salmond and have spoken to Mr Brown.

Mr Salmond and Justice Secretary Kenny MacAskill took part in the Cobra meeting.

Earlier in the day, Cobra also met to discuss the London car bomb attempts.
In the early hours of Friday, two Mercedes containing petrol, gas cylinders and nails were found left outside the Tiger Tiger club in Haymarket and a nearby street but the devices did not detonate.

Police in the capital are checking CCTV footage in their investigation into the planting of the two car bombs.

Unconfirmed reports suggest police may have an image of a suspect leaving the vehicle left outside the Tiger Tiger club.

Police increased patrols and security for events in London over the weekend, including the Gay Pride parade, the Concert for Diana at Wembley Stadium and the Wimbledon tennis championships.

Police have urged anyone with information to phone the confidential Anti-Terrorist hotline number on 0800789321.