The A38 has been closed in South East Cornwall after a fuel tanker crashed onto its side spilling up to 10,000 litres of fuel across the carriageway and damaging the road surface.
The route closed at 7pm last night, stayed closed through the night and police say it will need to be partially resurfaced before it can reopen.
Police said the road would be closed until at least mid-morning today, Friday - with a possibility it could be closed all day.
At 11am they revealed parts of the road will need to be resurfaced before it can safely be reopened.
Emergency services are still at the scene and it has yet to be cleared - a police spokesman said that even after it has been cleared resurfacing will have to be undertaken.
There are diversions where the road is shut at Tideford and Carkeel - along the A388 and A390.
Traffic is being sent through Callington.
At 6.54pm emergency services were alerted to a fuel tanker having crashed onto its side on the A38 at Tideford.
There were reports the lorry had jacknifed spilling 38,000 litres of diesel.
The figure was later revised to up to 10,000 litres spilled, with another 3,000 to 4,000 left inside the tanker. Emergency services revealed the fuel was unleaded petrol.
Cornwall Fire Service says the tanker had become disconnected from the cab of the lorry.
Three fire crews from Saltash, which includes an Enviromental Support Vehicle and a Rescue Tender from Bodmin, were on scene.
By midnight fire, police and Highways Agency staff were still at the scene assessing the damage to the road surface and overseeing the recovery of the vehicle.
Stocks of fire fighting foam and specialist equipment were sent to the scene by Devon Fire and Rescue Service as a precautionary measure.
At 4am specialist crews were decanting fuel from the overturned tanker and just before 7am they were ventilating fumes.
The tanker has to be fully ventilated before it is safe to move.
There are fears fuel may have got into the nearby river. An Environment Agency spokesman said pollution inspections would be carried out this morning.
Booms have been deployed to contain any fuel on the River Tidy - a salmon spawning ground.
The A38 remains closed in both directions (east & west) with diversions along the A388 and A390.
No injuries have been reported as a result of the incident.
The road remained closed through the night, and is unlikely to fully re-open until at least mid morning, but there are fears the difficult removal and clean-up operation could take much longer.
All services are working hard at the scene to enable the road to be opened as soon as it is safe to do so.
