A lorry carrying hay bales which caught on hearth on the M25 has brought about important delays to site visitors.
The anti-clockwise lane in Hertfordshire is closed between J25 Waltham Cross Interchange and J24 Potters Bar Interchange.
The traffic inside the road closure is in the process of being released.
National Highways said it expected two-hour delays and 13 miles of congestion from J27.
In a post on X, it said: “Please be patient, we’ll try and get you moving again soon.”
It reported the incident at 5.50am on Tuesday and said Hertfordshire Fire and Rescue, London Fire Service and National Highways were in attendance.
London Fire Brigade said: “Four fire engines and around 25 firefighters have been tackling a lorry fire on the M25 between Junction 25 and Junction 24.
“Crews have been working hard and a small part of the HGV remains alight. Please avoid the area if you can.”
Another collision on the M1 on Tuesday morning caused a lorry to overturn and spill 350 litres of diesel.
The crash, which occurred northbound between J10 Luton and J11 Dunstable in Bedfordshire, has closed three out of the four lanes for a recovery operation.
There is expected to be a 90-minute delay and nine miles of congestion as National Highways reports it will take time to clear the incident.
A “serious collision” also took place on the M11 in Cambridgeshire after a crash involving four vehicles.
The East of England Ambulance Service was called to the accident just before 4.50am on Tuesday, and the M11 is now closed in both directions between Junction 11 and Junction 12 for Cambridge.
An East of England Ambulance Services spokesperson said: “We sent multiple vehicles, including four ambulances, a vehicle from the Hazardous Area Response Team (HART) and a response car from Essex and Herts Air Ambulance. Three patients, including one who had sustained serious injuries, were transported by road to Addenbrooke’s Hospital for further treatment.”
Earlier this month, the M25 was closed after a lorry carrying rubber car tyres burst into flames across four lanes of traffic.