Britain raises security alert level to "critical"

LONDON (Reuters) - Britain has raised the national security rating to "critical", the highest level which indicates an attack is expected imminently, the Home Office said on Saturday.

The decision follows a car-bomb plot that was uncovered on Friday in which two cars loaded with fuel and nails were deployed to detonate in central London.

It also comes after a four-by-four vehicle was driven into the terminal at Glasgow airport and exploded on Saturday.