A major section of the M25 was shut overnight after a fatal collision involving a van and a tanker.
Police confirmed a man, aged 58, died at the scene after his silver Volkswagen Transporter van crashed between junctions five and six in Godstone, Surrey, at around 11.15pm last night.
Hundreds of drivers were trapped for hours after three lanes in the clockwise direction were closed while emergency services worked at the scene.
The busy motorway re-opened at around 5am, police said.
Witnesses reported seeing cars turning and driving the wrong way back up the motorway after the crash.
Andrew Phillips tweeted: ‘Cars have begun 3 point turns and heading neck (sic) the wrong way up the m25. Presume we shouldn’t?!
‘Huge flow of traffic the wrong way on m25 – presumably directed by police? We really need an update on what we should be doing!’
Another driver said traffic was not being directed by police but instead drivers were turning around and driving along the hard shoulder ‘on their own initiative’.
Highways England later confirmed that traffic was being allowed past the crash scene in the fourth lane.
Surrey Police’s Roads Policing Unit tweeted last night: ‘M25 junction 5 > 6 is CLOSED while we deal with a fatal collision.
‘If you are stuck between junction 5 and the scene, please be patient.
‘@HighwaysSEAST officers will be coming to assist but this will take a long time to implement.’
Drivers were diverted at junction five, via the A21 south and A25 west, to junction six.
A spokesman for Highways England added: ‘I can confirm there is now full closure of J5 M25 clockwise.
‘This will also include a closure from the A21 #Sevenoaks and a closure from the #M26 J2a on to the M25 and this is due to a serious incident .
‘Please be advised it may be closed for some time.’
Paramedics, police officers, Highways England staff and firefighters attended the scene.
All lanes have now reopened, Highways England said.
Police are appealing to motorists who witnessed the collision, stopped at the scene or who have dashcam footage, to call police quoting incident reference PR/P19255891.