Al Qaida plotting to attack UK transport hubs

London: Al Qaida is plotting car bomb, suicide and Mumbai-style attacks on crowds at British airports and train stations, a secret government memorandum discloses.

An alert issued by the security services warns of plots against transport hubs by Al Qaida's "international operations wing" designed to cause "a large number of casualties".

The "restricted" document, seen by The Daily Telegraph, details plans for "one or more attacks against Europe, including the United Kingdom", aimed at "high-profile Western targets".

It warns of attacks against British airports and the London transport network — including the Underground — with the aim of inflicting "political, economic and psychological" damage.

Terrorists, it says, could use "vehicle-borne" or "hand-delivered" bombs and firearms. The memo, dated on Thursday and sent to airlines, airports and cargo carriers by the Department for Transport, said the threat was "credible".

It originated at the Joint Terrorism Analysis Centre, part of MI5, sources said.

"No announcement about the aviation or London transport sector threat level changes will be made to the media," it adds.

The threat level was raised from "substantial" to "severe" for transport hubs, meaning an attack is "highly likely".

It has led to British Transport Police calling in extra officers.

David Cameron said in his New Year message that the terrorist threat was "as serious today as it ever has been" and that police and the security and intelligence agencies were "working around the clock to foil plots that would do terrible harm to our people and our economy".