MercoPress. South Atlantic News Agency

Mayor UK air terror plot thwarted

A major terrorist plot to allegedly blow up aircraft in mid-flight has been thwarted.

The plot was foiled in a joint intelligence-led operation by the Metropolitan Police's anti-terrorist branch and security service.

It is believed the aim was to detonate explosive devices smuggled on board the aircraft in hand luggage, and that the attacks would have been targeted flights from the UK to the USA. Overnight, police arrested a number of people in London.

Following the operation the threat level posed by terrorism to the UK was raised by MI5 to critical.

A statement on its website said: "This means that an attack is expected imminently and indicates an extremely high level of threat to the UK."

Thursday's arrests are the culmination of a major covert counter-terrorist operation lasting several months.

A Metropolitan Police spokesman said: "We would like to reassure the public that this operation was carried out with public safety uppermost in our minds.

"This is a major operation which inevitably will be lengthy and complex."

Following Thursday morning's police action, security at all UK airports has been increased and additional security measures have been put in place for all flights.

British Airways said any of its passengers who failed to comply with restrictions on luggage and other items would not be allowed on its planes. A spokesman said: "Customers are advised to check in as normal but to expect delays at all UK airports."