Drivers are dealing with long delays and road closures following a collision, which has led to a "substantial" fuel spillage.
The M40 in Buckinghamshire is closed southbound between J6 (Lewknor/Watlington) and J5 (Stokenchurch).
Traffic officers from National Highways are in attendance alongside Buckinghamshire Fire and Rescue Service.
The transport authority reported a "substantial fuel spillage", noting that service providers are at the scene.
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Traffic is building up along the major motorway following the road accident
|NATIONAL HIGHWAYS
According to transport provider Oxford Tube, there is an "overturned vehicle" on the M40, meaning all of its buses are being diverted via the A34 and the M4.
As a result, Oxford Tube's stop in Lewknor is out of service as the buses head between Oxford and London.
Traffic maps from National Highways suggest that the event is expected to clear by midday, with normal road conditions returning at a similar time.
National Highways is also reporting that the accident, which involves an overturned vehicle", is currently active.
Road users are advised to follow the hollow circle diversion symbol on road signs
- Exit the M40 at J6 onto the B4009
- Turn right on to A40
- Continue on the A40 and rejoin the M40 at J5
A collision has caused six miles of congestion on the approach, which could add more than an hour of travel time to people's journeys.
Traffic maps show standstill conditions between J6 and J5 on the M40
|NATIONAL HIGHWAYS
National Highways warned: "If you're travelling from further afield, you may wish to consider using the M1.
"If this closure impacts on your planned route, please allow extra journey time. Plan ahead, you may wish to re-route or even delay your journey."