A ‘suicide bomber’ simulated the detonation of an 'explosive' device at the Trafford Centre in an exercise designed to help the emergency services prepare for the event of a real-life attack.

Hundreds of volunteers made the drill as real as possible to give emergency services a chance to see how they would cope in the unlikely event an actual attack took place.

At midnight at the entrance by The Orient food court the exercise began when a man dressed in black walked in and shouted at the crowd who were pretending to eat and shop.

Watch: Armed police respond to the 'attack'

Video thumbnail, Video shows armed police responding to 'bomb attack' at Trafford Centre during exercise
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Moments, later an explosion rocked the food hall and volunteers - wearing ear defenders and safety glasses - dropped to the floor.

Many were made up to look as if they had horrific injuries and others screamed out as if in pain.

Smoke filled the entrance to the food court and some of the volunteers ran from restaurants, as if they were trying to dash to safety.

RECAP: Relive the events of last night's exercise

Our sister website the M.E.N. was one of a few media organisations allowed into the Trafford Centre to observe the counter terrorism operation, dubbed Exercise Winchester Accord.

The sound of gunfire could be heard ringing out through the food court as the volunteers screamed for help.

Moments later a masked gunman appeared near at the foot of the steps at the entrance to The Orient, firing a number of shots.

Watch: Armed police respond to suicide bomber

Video thumbnail, Armed police respond to 'suicide bomb attack' at Trafford Centre during exercise
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Earlier, the volunteers had gone through a safety briefing and had been reassured that no live rounds would be used.

After observing the initial ‘attack’, the media were asked move outside to witness the arrival, about five minutes later, of armed police.

Two armed police officers - carrying what appeared to be rifles - moved cautiously towards the entrance, weapons pointing out in front of them.

Armed response. Intu Trafford Centre, Trafford, Manchester, United Kingdom. Police in Greater Manchester have joined forces with other agencies to carry out a simulated terror attack to test the emergency response to a major incident. 10 May 2016. Photograph Credit : Sean Hansford

One covered the other as the pair went inside the food court, ignoring the ‘injured’ as they passed them.

It was at that point the media were asked to leave although the Trafford Centre part of the exercise was due to continue until 6am.

The shopping city will be open as usual today, although the training exercise is set to continue unseen at unnamed locations until Wednesday when it will finish in Merseyside.

The test, five months in the planning, is the latest in a series which have taken place across the country with the chances of a real terror strike said to be ‘likely’.

Greater Manchester Police, the North West Counter Terrorism Unit and the North West Ambulance Service were all being tested as part of the exercise, with no personnel being told precisely how the ‘attack’ would unfold.

A casualty. Intu Trafford Centre, Trafford, Manchester, United Kingdom. Police in Greater Manchester have joined forces with other agencies to carry out a simulated terror attack to test the emergency response to a major incident. 10 May 2016. Photograph Credit : Sean Hansford

Our sister site the M.E.N. understands the SAS were also involved in the operation.

Residents living nearby had been warned they could hear loud bangs and see emergency crews taking part in the test.

Following deadly attacks in Paris and Brussels, the terrorist threat remains ‘severe’ according to MI5.

However, counter terrorism police say there is no specific threat against Trafford Centre, which has been chosen because the exercise can take place away from the public at that time of night.

Injured shoppers. Intu Trafford Centre, Trafford, Manchester, United Kingdom. Police in Greater Manchester have joined forces with other agencies to carry out a simulated terror attack to test the emergency response to a major incident. 10 May 2016. Photograph Credit : Sean Hansford

Similar operations have taken place around the country including one involving 1,000 police officers in London last year.

None of the emergency services taking part in the exercise nor the volunteers have been told precise details of the scenario which will unfold, although they know it will involve some sort of terrorism attack.