Three people have been killed and 50 injured, some of them seriously, as a coach returning from a music festival overturned after hitting a tree on an embankment.
Emergency services were working at the scene to remove the dead from the coach which was heading back to the Merseyside area following the Bestival event on the Isle of Wight.
Police said the coach was travelling north on the A3 near Hindhead in Surrey at 11.50pm last night when it left the road between the Hindhead tunnel and the exit for Thursley.
No other vehicles are believed to have been involved.
Three people aboard, including the driver, were declared dead at the scene and a fourth passenger was airlifted to Southampton General Hospital with life-changing injuries, Surrey Police said.
South East Coast Ambulance NHS Foundation Trust (SECAmb) said 50 people from the coach - all the survivors - were taken to hospitals around the region, some of them with serious injuries.
Inspector Richard Mallett, of Surrey Police, briefing reporters at the scene, said it was not believed that road conditions or the weather were a factor in the crash.
Casualties were taken to the Royal Surrey County Hospital in Guildford, St Peter's Hospital in Chertsey, St George's Hospital in Tooting, King's College Hospital in London, Frimley Park Hospital and Queen Alexandra Hospital in Portsmouth.
The coach is understood to have been operated by the company MerseyPride and Surrey Police are working with their counterparts in Merseyside, as well as with the company, to identify the passengers and notify relatives.
Some passengers were taken to a rest centre set up nearby by Waverley Council.
Surrey Police Assistant Chief Constable Jerry Kirkby said: ''This has been declared a major incident and we are working with our colleagues from the other emergency services and other partner agencies to provide a co-ordinated response in line with agreed protocols.
''Our thoughts remain with the relatives of the dead and the injured at this time and we are working very hard to notify their next of kin.''
The road is expected to remain closed for several hours and diversions have been put in place. Motorists are being asked to avoid the area until the road reopens.
Mr Mallett, speaking to Sky News, said: ''We are dealing with a major incident, a tragic major incident. The coach has gone off the road and had a significant impact with a tree, I think that is the best way to describe it.''
Updating reporters later, he said one body had been removed from the coach and two more were still to be recovered.
''The injuries range from life-changing injuries - some people were unconscious when they were taken away from here - we believe some people might lose limbs and certainly there are some life-changing injuries amongst the survivors.
''The priority is to get the people out of the coach and then we can really begin to look at forwarding the investigation.
''We don't think that the road conditions or the weather were a factor in this.''
Asked how long the coach had been on the road, he said: ''We understand that it left the Isle of Wight festival so we are less than an hour from Portsmouth where they come across.
''So less than an hour of this journey. As to what the previous was, we don't know. Again, we need to make sure that we get the people out properly and then we can start looking at things like tacho charts and forwarding the investigation.''