TERROR IN THE UK

A plot to blow up planes in flight from the UK to the US and commit "mass murder on an unimaginable scale" has been disrupted, Scotland Yard has said.

It is thought the plan was to detonate explosive devices smuggled in hand luggage on to as many as 10 aircraft.

Police were searching premises with 21 people in custody after arrests in the London area and West Midlands.

High security is causing delays at all UK airports. The threat level to the UK has been raised by MI5 to critical.

According to MI5's website, critical threat level, which is the highest, means "an attack is expected imminently and indicates an extremely high level of threat to the UK".

Heathrow Airport has been closed to all incoming flights that are not already in the air, while several outbound services have been cancelled.

The airport is crammed with thousands of passengers, while at Stansted more than 2,000 people are queuing to pass through customs.

Metropolitan Police Deputy Assistant Commissioner Paul Stephenson said the alleged plotters had intended "mass murder on an unimaginable scale". "We are confident that we have disrupted a plan by terrorists to cause untold death and destruction and to commit, quite frankly, mass murder," he said.
"We believe that the terrorists' aim was to smuggle explosives on to aeroplanes in hand luggage and to detonate these in flight. We also believe that the intended targets were flights from the United Kingdom to the United States of America. I can confirm that a significant number of people are currently in custody and the operation is ongoing."

The majority of the arrests were in London with some in the Thames Valley and Birmingham, he said.
Police had spoken to a "good number of community leaders to make them aware that a major operation was under way," he added.

According to BBC sources the "principal characters" suspected of being involved in the plot were British-born. Arrests were made in High Wycombe, London and Birmingham.
BBC home affairs correspondent Andy Tighe said police sources had told him they had found "interesting items" which were being examined.

The US Department of Homeland Security increased the threat level applied to US-bound commercial flights originating in the UK

The Home Office confirmed there had been three meetings overnight and on Thursday morning of the Cabinet's emergency committee, Cobra, chaired by Home Secretary John Reid, to discuss the terror alert

A spokesman for Number 10 said Tony Blair had briefed US President George Bush on the situation during the night

All passengers were banned from taking hand luggage onto flights, while the government warned of delays.

BBC home affairs correspondent Daniel Sandford said he did not think the police believed an attack was imminent now there had been arrests.

Joe Lynam, a BBC journalist at Gatwick,"The reason for raising the threat level is in case there is some other sub-plot, back-up plot around this that the police aren't aware of," he said.

BBC security correspondent Gordon Corera said given that most liquids were being banned from flights it suggested the suspected plot involved "some kind of liquid explosive".
He also said the plot had an "international dimension", while the investigation had involved the CIA. "The Americans have definitely been involved for quite some time," he said.

Prime Minister, Tony Blair is on holiday in the Caribbean, but Downing Street said the police operation was undertaken with his full support and he had been "in constant touch".

The current threat level is assessed as critical as of 10th August 2006 - this means that an attack is expected imminently and indicates an extremely high level of threat to the UK

Passengers are only allowed to take on board only the barest essentials including passports and wallets which will be allowed to be carried on board in transparent plastic bags.