Police have launched an appeal for witnesses after a man crashed into a ditch on the A259 on Romney Marsh this morning.

The 18-year-old from the Rye area suffered a serious head injury and was unconscious as he was flown to St George's Hospital in London, emergency services confirmed earlier today.

A police spokesman said: "At 8.30am a purple Renault Clio was travelling along the A259 Rye Road in Brookland.

"But as it approached a right-hand bend near the entrance of a haulage yard, the driver lost control and collided with a tree."

Police said this afternoon the man is still in a serious condition.

Rush hour traffic ground to a halt as two fire engines, two ambulances and several police cars rushed to the main road between Ashford and Rye, along with the air ambulance.

The KM Group's political editor Paul Francis was on the scene after being caught in the queues on his way to work.

He said: "There's quite a sharp bend in the road and it looks like someone has swerved and the car has gone into the ditch.

"Firefighters and ambulance crews are helping the person in the car."

Kent Fire and Rescue Service said the man was unconscious when he was cut free from the car and was taken into the care of paramedics.

An air ambulance spokesman said the man was treated by their paramedics and doctor before being taken in the helicopter to St George's, where there is a major trauma centre.

Kent Highway Services said the road was closed from the Hook Lane junction to Brookland roundabout.

The crash happened close to the Sussex border so emergency services from both counties worked together.

The road reopened earlier this afternoon after being closed for about five hours.

Anyone with information about the collision or who saw the car just before the crash is urged to call the SCIU appeal line on 01622 798535.