Essex Police had already closed off the carriageway, when a car drove towards them the wrong way.Read more
Three children were among 13 Iranian migrants detained by immigration officials at a service station on the M25.
A group of people were filmed climbing out the back of a lorry in Clacketts Lane.
Police and Immigration Enforcement officers were called to the scene.
The Home Office said: "Thirteen Iranian nationals were taken into custody. They will be interviewed by immigration officers and their cases will be dealt with according to the immigration rules."
Two boys are being sought by police after motorists reported rocks being thrown from a footbridge on to the M25 motorway.
It happened at about 17:50 BST on Sunday close to junction 11, near Row Town in Addlestone, Surrey.
Police said the youngsters were aged about 14 years old, and were both wearing black jackets.
No-one was injured but four cars were damaged.
Highways England placed speed restrictions in the immediate area to help reduce the impact to vehicles and their occupants.
Any witnesses, or motorists with dash cam footage, are asked to contact officers.
MPs and police have raised concerns over people's safety on smart motorways.