A probe into what caused one of the worst crashes on the M25 in 20 years will take several days, police say.
It took more than an hour to free the injured man from the wreckage
The crash, in the early hours of Monday, left six people dead, five of whom were in a group travelling back from a stag party in Leicestershire.
The group, from Brighton, were in a rescue truck that was carrying their broken-down minibus when it collided with a lorry in Surrey.
The recovery vehicle driver, from Rugby, also died at the scene.
A sixth occupant of the minibus was also hurt but is stable in hospital.
The HGV driver was uninjured in the crash, which took place at 0215 BST, between junction 8 at Reigate and junction 9 at Leatherhead.
Chief Supt Rob Price, of Surrey Police, said it could be a number of days before the names of the victims will be released.
"A thorough investigation is being undertaken...and it will be a number of days before we will be in a position to release further details," he said.
"Our thoughts are very much with the families and friends of the six people who died in this tragic crash."
Seven people, one thought to be the groom, had earlier been picked up where the minibus broke down, on the M1.
They were returned safely to Brighton by one recovery vehicle from Dunchurch Motors Ltd.
The minibus was put on a second recovery vehicle and six members of the stag party group travelled in the cab with the driver.
The five Brighton men who died were aged between 25 and 30, police said.
The one surviving person was taken to East Surrey Hospital in Redhill with a broken leg and face injuries.
Police have confirmed the recovery vehicle was set up safely to seat seven people - one driver and six passengers - with proper seat belts.
The cab of the recovery vehicle was completely destroyed in the accident, which left wreckage strewn across both carriageways.
The lorry driver is being treated as a witness by police, who took more than nine hours to collect evidence and clear the motorway of wreckage.
"This is one of the worst collisions Surrey Police have dealt with on the M25," added Chief Supt Price.