In the event of a terrorist attack in Sutton how would emergency services respond?

From earlier: Major disaster looms for Sutton town centre as emergency services plan decontamination response - but it's only a drill

Our reporter Andrea Downey took part in an emergency training scenario between police, firefighters and the Red Cross at the Sutton Life Centre today to find out exactly that.

More than 50 volunteers played the part of injured and uninjured survivors, each assigned a character to play out for emergency service staff.

The scenario – ‘there was an explosion of several drums of hazardous materials in a van parked outside Carshalton train station, causing about 50 casualties, 20 of which were fatal.'

'And the explosion caused air contamination which caused skin and eye irritation and respiratory problems.

'75 uninjured survivors were taken to the Survivor Reception Centre suffering from shock and trauma.’

Here’s what happens next for the victims.

Within the first hour of local police responding to the incident more than 20 police will be on site as well as ambulances and the fire brigade.

More emergency services will be deployed to arrive at the scene as soon as possible.

Casualties are assessed by medics from London Ambulance Service on site and sent to hospital or the Survivor Reception Centre, provided by the local authority.

They are then taken through a de-contamination tent run by the fire brigade to remove all harmful materials from the explosion.

Both ambulance and fire officers wear HAZMAT suits and a breathing apparatus to protect themselves from harm – quite a confronting site to be faced with after you’ve been caught in a terrorist attack.

Once de-contamination has taken place victims were interview by police trying to piece together the events that unfolded during the attack.

The Red Cross then step in and provide emotional and practical support for the victims, who are allowed to stay in the survivor centre for as long as they need.

It is at this stage that survivors can ask officials to contact loved ones to let them know they are OK.

It all seems like a lot to manage between all the parties involved but it runs smoother than expected.

Victims are left with no doubt emergency services know what they are doing.

Sutton Town Centre Supervisor Police Sergeant Simon Alexander said: “Fortunately, because these things are so few and far between in Sutton, it is something that we don’t do on a regular basis so this prepares on for that eventuality.

“Hopefully it never happens but if it does we know that we can put into practice what we learn from these training scenarios.

“Each organisation will take a learning experience away with them as well, so it’s a case of learning how we all work better together.”