A woman has been airlifted to a major trauma centre in London after a serious accident on the M25.

The motorway was closed between junction 4 for the A21/A224 and junction 5 for the M26/A21, but is now fully re-open, although traffic remains heavy.

It follows a crash on the anti-clockwise carriageway just after 1pm.

A female motorcyclist, believed to be in her 40s, has been airlifted to St George's Hospital in London after sustaining serious head injuries.

Both the clockwise and anti-clockwise carriageways were closed to allow the air ambulance to land earlier today.

The clockwise carriageway was reopened at 2pm but one lane of the anti-clockwise carriageway was down to one lane for much of the afternoon to allow for forensic investigation.

Witnesses to the collision are asked to contact Kent’s Serious Collision Investigation Unit on 01622 798538.

Police are also keen to remind people to stay in their vehicles if they are stuck in stationary traffic.

This follows reports of people playing football in the carriageway and a report of two teenagers being stranded on the wrong side of the M25 after the clockwise carriageway was reopened.

The pair had reportedly walked across the motorway whilst the road was closed, but then were unable to get back when the road was reopened.

A patrol helped them return to their vehicle safely.