DOZENS of people were exposed to a dangerous chemical yesterday at a lecture theatre of the Met Police's training centre in Colindale.

Around 80 firefighters attended the scene and set up emergency decontamination equipment to deal with the situation, while police sealed off the scene and St John's Ambulance crews treated casualties.

However, this was not a terrorist attack or accidental leak, but a drill to sharpen the skills of emergency crews in the area.

The scenario played out involved about 50 people in a conference centre reporting symptoms of chemical poisoning, testing the responses of both police, who as first on the scene take charge and establish what is happening, and fire crews.

During the drill firefighters from Hendon and Mill Hill stations, which were the first on the scene, donned special suits to investigate the leak.

They then led groups of people through a shower set up using two hose reels between two fire engines. Later decontamination tents with warmed water in the showers were used to help those most seriously hit by the contaminants.

Ray Newstead, a member of the Hazmat team for the London Fire Service, said: “We're training seven day a a week carrying out these type of drills across the country.

“From an observers point of view it may seem like the process is fairly slow, but it's very structured.”

Chief Inspector Phil Halsey also attended to monitor how the police's response was handled.

He said: “The police are here to take charge of everything and lock down the perimeter so nobody can get in and out.

“Our main responsibility is to manage the scene and when it has been made safe launch the investigation along with the fire services.”

Another aspect of the drill was to see how well the emergency workers dealt with people with religious sensitivities, with a group of Orthodox Jews among those affected.

Adrian Jacobs, a member of the Community Safety Trust, was there to act as an observer and adviser.

He said: “There are issues around modesty and things like that. There are some Orthodox members who would absolutely refuse point blank to take their clothes off unless there were separate showers for men and women.

“My role today is to see how well they deal with that and then give them feedback afterwards.”

Mayor of Barnet Councillor Brian Coleman also dropped in to see how the event was progressing in his role as the chairman of the London fire Authority.

He said: “It looked to all be going very well. It's a very useful exercise and shows the amount of money which has been invested by the Fire Authority on new equipment.

“The huge decontamination tents and equipment they put up were all bought within the last five years. We have spent £10m investing in first class equipment.”