THE scale and complexity of last week's multi-vehicle accident on the M20 was responsible for the road being closed for nine hours, say Kent Police.

The fatal accident happened at Addington, near West Malling, on Wednesday last week.

In a statement issued on Tuesday, Kent Police said: "During the closure period police and other emergency services dealt with casualties, closed the road, cleared a lengthy tailback, carried out a comprehensive crash investigation, cleared debris and fuel spills, ensured the road was safe and carried out a search for three people who disappeared from the scene.

"While officers were still dealing with this incident traffic crews also dealt with two other crashes further down the M20, near Ashford.

"The combination of circumstances led to long delays and Kent Police has thanked motorists for their patience."

Chief Constable Mike Fuller said: "Our priorities at fatal crash scenes are to prevent further loss of life or injury, ensure emergency crews can treat and remove the injured, investigate the causes of the crash for HM Coroner and secure evidence for any subsequent court proceedings.

"We have to treat fatal crash scenes in the way we treat all unexplained deaths, but on the roads we only get one chance to examine the scene.

"We also try to minimise disruption. We have reviewed the sequence of events last Wednesday and, given the complexity of the incident, the number of vehicles involved and the tragic death of a young man I am satisfied that officers performed their duties as quickly as they could, consistent with the proper investigation of the killing."

He said the force had been in discussion with Kent County Council about putting statutory diversion routes in place that would allow traffic flows to be redirected and reprioritised in an emergency, using a planned network of suburban roads.

This would need engineering and signage work to help manage congestion and might require new legislation.

The chain of events on Wednesday last week started with the multi-vehicle pile-up at 1.40am.

The police statement continued: "When officers arrived the scene stretched for 500 yards and debris was scattered across all three lanes and the central reservation.

"One man had died and two people were seriously injured. Officers at the scene said it was a miracle there was only one fatality, given the nature and severity of the accident.

"Five vehicles, including a lorry and a van, were strewn across the road. Behind the crash a lengthy tailback had developed.

While emergency crews dealt with the casualties, police and Highways Agency officers had to close the roads and get traffic off the motorway.

"With all lanes blocked between the accident and previous slip road, this involved the slow and painstaking task of turning vehicles, including many heavy lorries, round and taking them in convoy the wrong way down the motorway and off at the slip road, again in the opposite direction to the normal traffic flow.

"Officers had to work from the back of the queue to the accident scene. Vehicles closest to the crash had to be reversed in case there were further casualties and to avoid damaging evidence and disrupting the scene.

"This required careful policing and traffic management and took three hours to complete. The motorway had already been closed to other traffic.

"At 5am, when the road was clear, specialist crash investigators were able to start examining the scene.

"This involved measuring the vehicles where they had come to rest, examining and logging the scatter of debris, gathering forensic evidence, identifying and recording skid marks and where the vehicles had made contact with one another.

"The size of the scene and number of vehicles meant this took four hours. The task involved piecing together many fragments of debris to work out the sequence of events.

"The debris and spilled fuel also needed to be cleared from the road and safety checks carried out before it could be reopened to traffic.

"While this was happening a search was launched for three people seen to leave the scene. It was not known whether they were injured, so police dogs and a helicopter were called in to search for them.

"Officers still want to talk to the three, who had been travelling in a Vauxhall Astra, and anyone else who witnessed the incident, including the occupants of two vans who may have narrowly avoided the crash."

Anyone who can help is asked to call Kent Police's serious collision witness line on 01622 798538.