Three teenage girls have been taken to separate hospitals after the car they were travelling in was involved in an accident on the A20 in Kent.
Their Ford Fiesta was travelling from Ashford towards Charing when it left the road and hit some trees near Charing Crematorium at 1130 BST.
The driver and a back-seat passenger were seriously injured and flown to hospitals in London by air ambulance.
A front-seat passenger was taken by land ambulance to hospital in Ashford.
The 17-year-old girl is in a serious condition.
Essex Air Ambulance took the 18-year-old driver to King's College Hospital, where she is in a stable condition.
Surrey Air Ambulance flew the 15-year-old passenger to the Royal London but she was later transferred to Great Ormond Street, where she is in a critical condition.
Kent Air Ambulance was called out to two other accidents on Saturday morning.
In the first, a man in his 70s from Surrey received chest injuries when his car left the road and hit a lamp-post, fencing and two concrete bollards outside the King's Head pub in North Street, Sutton Valence.
The air ambulance landed nearby, but the man was taken by road to Maidstone Hospital. It is not thought his injuries are life-threatening.
In the second, an elderly couple were injured when they were hit by a car travelling north towards Tonbridge on the A26 at Southborough.
The woman was flown to King's College with a serious head injury.
The man was taken by land ambulance to the Kent and Sussex Hospital in Tunbridge Wells with minor injuries.