At least six people were killed and several others seriously injured in an accident yesterday as motorists made their way home from the South Coast. Sussex Police described the scene on the A23 north of Brighton as "carnage".
The dead are believed to include three men and three women.
Four or five vehicles on both sides of the dual carriageway are believed to have been involved in the crash. Police think that one car ploughed through the central reservation into the path of oncoming traffic.
A four-year-old boy, a woman in her twenties and a man in his thirties were among the most seriously injured. At least three people had to be cut free by firefighters. Several people with minor injuries were taken to hospital after being given first aid at the scene.
The accident happened at 4.30pm, just north of Brighton, as thousands of people made their way home after one of the hottest days of the year so far.
Police categorised the crash, close to the junction of the A23 and the A27, as a major accident. They also quickly warned of serious traffic problems throughout West Sussex.
A 10-mile stretch of the A23 the main London to Brighton road was closed in both directions and was expected to remain shut "for some time" as police and fire officers tried to free casualties from several crushed vehicles.
The four-year-old boy was being treated last night in the intensive-care unit at the Royal Sussex County Hospital in Brighton. A hospital spokesman confirmed that the child had been admitted suffering from "very serious injuries".
Other casualties were taken to the Princess Royal Hospital in Haywards Heath, including the young woman, said also to be in a very serious condition.
Several fire crews, six ambulances and police attended the scene, between Patcham and Pyecombe. "It was a horrific crash, involving at least seven vehicles," the Sussex Ambulance Service spokes-woman said. "There have been a number of fatalities at the scene. Six others have been taken to hospital ... A senior paramedic said that it was one of the most horrific incidents he had attended."
Police were trying to establish the cause of the pile-up last night. A spokesman said: "We are looking at the possibility that a car travelling south has crossed the central reservation and been in collision with a number of vehicles in the northbound lane."
Roads from Cornwall to Sussex were already clogged when the accident happened, with the A23 one of the busiest routes, as thousands made their way home from coastal resorts. Temperatures in southern England had been almost 10C above the monthly average.