A lorry fire is causing major hold-ups for commuters in Essex.
Traffic is being held both ways on the M25 between junction 27, for the M11, and junction 28 at Brentwood.
Highways England says a diversion is in place and police and firefighters are on the scene.
Drivers in Essex are being warned that two slip roads linking the M25 and the M11 are still closed following a serious crash overnight.
The slip road from the anti-clockwise M25 to the northbound M11 and from the northbound M11 to the clockwise M25 are both closed after a lorry a lorry struck a bridge and overturned just before midnight on Sunday night.
Drivers approaching the closures are being directed to continue to the next junction, where they can turn around and approach the junction in the other direction.
Essex Police are investigating the incident and there is is debris and diesel to clear from the road. The bridge that was struck will also need to be assessed, and the carriageway may need to be resurfaced due to the diesel spillage.
A man arrested on suspicion of causing death by dangerous driving following a fatal crash on the M25 in Essex on Tuesday 9 December has been transferred into the care of mental health professionals.
The 25-year-old was arrested at Princess Alexandra Hospital where he was being treated for injuries he had sustained during the collision.
He will be interviewed at a later date pending the advice of doctors.
The crash is understood to have involved a lorry crossing the central reservation.
The M25 in Essex is closed in both directions between J23 (A1) - J27 (M11) clockwise, and J27 (M11) - J25 (Cheshunt) anti clockwise. The carriageway may not fully reopen until 3pm.
The Highways Agency has released a time-lapse video of work to make it quicker and easier to pay the toll for using the Dartford Crossing between Essex and Kent.
The video shows the installation of five new gantries that have been installed at the entrance to the Dartford tunnels and on the Queen Elizabeth II bridge.
The gantries will hold cameras and sensors for the new Dart Charge being introduced in October. That will allow drivers to pre-pay the charge or pay online so they won't need to stop at the toll booths.
The Highways Agency says 170,000 vehicles a day use the crossing and the new system will improve journeys and reduce congestion.
Drivers are being warned the M25 anti-clockwise will be closed during Thursday's rush hour after a lorry fire.
The M25 is closed anti-clockwise between junction 23 (access to the A1(M)) and junction 21a (access to the M1).
A lorry carrying cooking oil and foodstuff has overturned, spilling its content – which later caught fire – onto the carriageway.
Emergency services are currently on scene, as well as structures engineers assessing damage to the road and overhead gantry.
A police investigation is underway. The road will be reopened as soon as it is safe to do so but the closure is expected to last for several hours, and during rush hour.
Road users wishing to use the M25 anti-clockwise need to exit the M25 at junction 23 and take the A1(M) north; exit at junction 3 and join the A414 west. Take the A405 south and rejoin the M25 at junction 21.
Police are advising drivers to avoid the M25 until mid-afternoon after a lorry fire closed the carriageway on both directions in Hertfordshire.
The section between junctions 21a and 23 near the South Mimms services is expected to be closed until 3pm.
Long tailbacks have built up on surrounding roads.