Hundreds of police and emergency services personnel conducted the drill in the Square Mile to test how well emergency services would react to a terrorist strike. Police closed off a subway station and surrounding streets for the exercise.
The Department of Transport said the drill, the first large-scale exercise since the Sept. 11 terrorist attacks in the United States, was not a response to a specific threat.
``Most people realize that we live in extremely difficult times. We've got to prepare against all sorts of eventualities,'' Transport Secretary Alistair Darling told Sky News television.
In the simulation, a subway train stopped in a tunnel on its approach to Bank station as if a chemical weapon was released on board.
Police cadets posing as passengers were evacuated and ``treated'' by emergency workers and Fire Brigade units using new $88 million decontamination equipment set up in tents above ground.
More than 350,000 people work in the Square Mile on an average weekday and the Bank of England, the London Stock Exchange and the official residence of the Lord Mayor of London are all located in the immediate area.
