Britain Expands State of High Alert

The intensified deployment came a day after the government, acting on intelligence about a possible terrorist attack, took the drastic step of stationing tanks and soldiers around the perimeter of London's Heathrow Airport.

British leaders had even considered shutting down Heathrow, the nation's top law enforcement official said Wednesday. But they decided that a shutdown would have caused great economic damage and amounted to surrendering to terrorism, Home Secretary David Blunkett said.

"For those who are threatening us, it would have been a victory," Blunkett said.

On Wednesday, troops patrolled western London suburbs under the airport's flight paths to guard against rocket attacks similar to the attempt by Al Qaeda members to shoot down an Israeli plane in Kenya in November.

"The symbolic importance of Heathrow indicates that it has got to be at the top of a terrorist's priority list," Michael Clarke, a professor at King's College in London, told the BBC. The chief of the London Metropolitan police, John Stevens, said the operation was the highest-level terrorist alert he's been involved in. And he said he hadn't ruled out sending troops into the streets of London, where the busy King's Cross rail station was briefly closed Wednesday evening because of a bomb scare. The threat turned out to be a hoax.

Special squads of armed police, meanwhile, began patrols at major airports in other cities, including Manchester, Bristol, Birmingham, Leeds, Stansted and Jersey, in the Channel Islands. Manchester police shut down an airport parking lot as a precaution.

The Manchester security operation resulted from "public concerns and fears, based on speculation, following the announcement of the use of military personnel at Heathrow and public concerns relating to the possibility of a forthcoming war against Iraq," said Chief Inspector Martin Gaffney, head of Greater Manchester Police.

A Scotland Yard spokesman called the mind-set of the authorities one of "alert, not alarm." Once a haven for leading Islamic extremists, Britain has been on guard for months. Working with French police, British law enforcement officials have made several dozen arrests aimed mostly at the Al Qaeda terrorist network, whose members allegedly scouted the London subway for a cyanide gas attack and produced ricin poison for another plot.