A prisoner is among four people to have been seriously injured after a prison van overturned in a crash on the A27.
The van collided with an HGV lorry near Lewes Prison in East Sussex shortly before 11am on Monday, Sussex Police said.
Three men inside the van – two escort officers and a prisoner – were taken to hospital with serious injuries.
A 29-year-old, believed to be the prisoner, suffered a head injury and was in a critical condition.
The lorry driver, a 58-year-old man, was also taken to hospital after suffering a serious head injury.
Fire crews, ambulances and police were all sent to the scene.
Four people in total were trapped in the collision, according to East Sussex Fire and Rescue Service, and images showed dozens of emergency service personnel working to free them.
The A27 was closed in both directions between Ashcombe and Southerham roundabouts following the crash and traffic in the area has been severely gridlocked.
Footage showed cars being turned around on the A-road.
Police have urged drivers to avoid the area, and in a Twitter update at 2pm said the A27 will “remain fully closed for some hours yet”.
The westbound carriageway may not reopen until the evening.
Ministry of Justice contractor GEOAmey confirmed its police van was involved in the crash.
In a statement, it said the three men injured inside the van were in “serious but stable” conditions.