(Associated Press) Britain said that police have foiled a plot to cause “mass murder on an unimaginable scale” by blowing up planes to the United States, putting the nation on maximum terror alert and snarling air traffic around the world. Police said 21 people had been arrested, most of them in the capital London and surrounding area, over the alleged plot in which terrorists would smuggle aboard explosives in hand baggage and detonate them. Home Secretary John Reid said the “very significant” plot was designed to “bring down a number of aircraft through mid-flight explosions,” and amounted to “a major threat to the UK and international partners.”
Mystech: Nice work, UK!


He later told a press conference that police were confident that “the main players have been accounted for.”

“Whilst the police are confident that the main players have been accounted for, neither they nor the government are in any way complacent,” he warned.

Prime Minister
Tony Blair’s office said the anti-terror operation had been undertaken “with the full support” of the premier, currently on holiday in the Caribbean.

His officials said he had briefed US
President George W. Bush.

Deputy Commissioner Paul Stephenson, of London’s Metropolitan Police, said the operation had disrupted a bid to cause “untold death and destruction”.

Arrests were made in London, the central English city of Birmingham and the Thames Valley region of southeast England, he added.

“We can’t stress too highly the severity that this plot represented. Put simply, this was intended to be mass murder on an unimaginable scale,” he told a news conference.

Deputy Commissioner Peter Clarke, head of the police’s anti-terror branch, said that they were in the “very early stage of a meticulous and painstaking investigation” that had begun months ago and “will last long into the future.”

The investigation had shown the devices were to be built in Britain and to be taken through British airports, he said, adding that the plot had “global dimensions.”

Clarke said police took “urgent action” overnight because the operation had reached a “critical point”, but did not elaborate.

The US Department of
Homeland Security said it had raised the threat level for commercial flights from Britain to the United States to the highest state, “Severe, or red.”

The threat level was raised to “High, or orange” for all other air traffic in and to the United States.

The security clampdown caused havoc at airports and forced many British and foreign airlines to cancel flights, stranding tens of thousands of passengers here and abroad.

In Britain, airport security was tightened as the alert level was raised to “critical” from “severe,” where it had been since security was relaxed in the weeks after the London transport attacks of July 2005 which killed 56 people.

British Airways cancelled all its short-haul inbound and outbound flights from London’s Heathrow Airport to destinations at home and across Europe until 4:00 pm (1400 GMT) Thursday.

Airports operator BAA requested the suspension of all flights due to take off for Heathrow from points worldwide.

Security was ordered to be tightened at British airports, where departing passengers were not allowed hand baggage except articles placed in transparent bags.

There were also restrictions on fluids. Those traveling with an infant were required for example to taste the contents of bottles of baby milk.

However, police did not confirm reports in the British media that the plot involved liquid explosives.

Long and chaotic lines formed at the nation’s airports, including Heathrow and Stansted outside London, as well as Manchester in northern England.

Stephenson said that the foiled airline plot concerned “people who might masquerade within a community behind certain faiths,” an apparent allusion to Britain’s Muslim community.

Last year, four suicide bombers — all Muslims who had grown up in Britain — killed 56 people in coordinated attacks on three London Underground trains and a bus, the worst terror attack on British soil.

Reid had said Wednesday that Britain faces “the most sustained period of severe threat since the end of World War II.”

He said that while the security services would deliver 100 percent effort and dedication, they could not guarantee a 100 percent success rate in fighting terrorism.

Rohan Gunaratna, of the Singapore-based Institute of Defence and Strategic Studies, said the Al-Qaeda network was the only group capable of planning such an attack, and that the plot bore its hallmarks.