More than 50 firefighters will be taking part in a full scale live overnight exercise dealing with the scenario of a major incident in the Dartford Tunnel.

Seven fire engines and specialist vehicles from west Kent along with firefighters from Essex Fire and Rescue Service will be called to the scene between 10pm and 2am to test the emergency services and other partner agencies response to a huge blaze.

The scenario, taking place on Saturday (MAY 10) after a van travelling in the west tunnel suffers a sudden tyre failure and swerves, colliding with a second vehicle.

The impact causes both vehicles to crash into the nearside walkway, blocking both lanes of the tunnel and causing long tailbacks.

The drama heightens when smoke is seen billowing from the van, activating the recently installed state-of-the art fire suppression safety system, part of a £34 million safety upgrade.

Greg Theophanides, Kent Fire and Rescue Services (KFRS) said: "Dartford Tunnel plays a vital role in keeping the county’s road network moving.

"However, fires in tunnels can be the most difficult to deal with and pose unique challenges.

"It can be harder for rescue teams to reach the scene, the conditions are confined and it gets incredibly hot and humid.

"This is why we must be able to put our emergency plans into operation effectively.

"The activation of the new fire suppression system will knock the fire back quickly, making it safer for our firefighters and tunnel users.

"Although safety standards in the tunnel are very high, it’s vital that our contingency plans are as robust as possible."

"This innovative training session will allow our firefighters to bring to life possible events that we could be called to deal with and make sure we are all equipped and prepared to deal with it safely and ensure the safety of motorists."

Paul Harding, Highways Agency Project Manager, said: "Safety is a top priority for the Highways Agency and, although we hope an incident like this never happens, we want to make sure that our teams and the emergency services are prepared.

"The tunnel safety systems have been upgraded to ensure that journeys remain safe for the thousands of drivers that use the Dartford Crossing each day."

The exercise will also include the Police, Ambulance Service, Essex Fire & Rescue Service, Highways Agency, local authorities, Environment Agency, St John Ambulance, British Red Cross and the Casualties Union and is taking place overnight to keep disruption to a minimum for travelling public.

Chris Brown, Connect Plus, (the Tunnel Operator on behalf of the Highways Agency), said: "Simulations like this are essential to ensure our readiness to deal swiftly and effectively with any incidents in the tunnels.

"The exercise also gives us the opportunity to ensure that the emergency procedures and equipment perform along with the ability of the organisations taking part to work together in an emergency situation."

Both tunnels will be closed between 10pm and 4am with a fully signed diversion for northbound traffic via the A2, A102 through the Blackwall Tunnel and the A13.

The northbound Blackwall tunnel has a height restriction of 4.0m (13’0") and is classed as ADR Category E.

Any vehicles above this height restriction or carrying dangerous goods will be required to use the clockwise M25.