A six-year-old boy was killed and four other people injured in a road crash that closed the M1 near Milton Keynes for three hours on Sunday.
Mohammed Aminul Islam, of Walsall in the West Midlands, was a passenger in an MG car that was in collision with a Peugeot on the motorway at 1345 BST.
The four other people in the MG, including another child, were taken to Milton Keynes General Hospital.
A woman travelling in the Peugeot was treated for minor injuries.
A 17-year-old, also a passenger in the MG, was airlifted to Stoke Mandeville Hospital. His injuries are serious but not thought to be life-threatening.
Two of the people from the MG were taken to Milton Keynes hospital. One, a woman aged 23, was later discharged while the other, an 11-year-old girl, remains in hospital in a serious condition. The driver was uninjured.
A 38-year-old female passenger in the Peugeot was taken to Milton Keynes hospital with minor injuries. The three others travelling in the car escaped unhurt.
Thames Valley police are appealing for witnesses to the accident.