London is carrying out a major exercise testing the ability to cope with a terrorist strike on its underground system Sunday, just days ahead of the second anniversary of the Sept. 11 attacks on the United States.

There have been concerns that terrorist groups might attack Britain sooner or later since the country sided with the United States in the anti-terror war and the war on Iraq.

The exercise, which began at midday and will last several hours, does not involve ordinary citizens or real chemicals, but is designed to test the response of the police, ambulance and fire services to a terrorist attack.

Government officials stressed that the exercise was not in response to any specific threat.

The scenario being acted out is that a chemical, thought to be something similar to the sarin gas used in the 1995 terrorist attack in Tokyo, is released on a busy train from Waterloo to BankTube station, in the heart of the City of London.

The exercise began when the train driver reported the attack and stopped the train in a tunnel 50 yards short of Bank station.

A government spokesman said a leaflet is handed to every "casualty" as they emerge from the station, which shows pictograms of the 16-stage decontamination process.

It shows how they have to wear a dust mask, cut clothing to avoid taking it over their heads and dispose of garments and valuables into plastic bags. They also have to don a disposable cape, gloves and shoes and an identification wristb and, the leaflet shows.

Sixty police cadets are playing the part of victims who are decontaminated on the street. Firefighters and paramedics are recovering the "casualties", bringing them to street level and decontaminating them in special shower tents.

The area immediately surrounding Bank station is designated the so-called "Hot Zone" and the decontamination units are set up in a surrounding "Warm Zone" upwind of the center of the site.

It is the first time a live operation of this kind has been carried out and is the first time the decontamination units have been seen in public in the country.

Britain had planned to hold the drill in March, only to be postponed due to the Iraq war.

(Xinhua News Agency September 8, 2003)