The A419 has been closed in both directions after a live power cable fell into the road.
Police have closed the stretch between Commonhead Roundabout (Great Western Hospital) and the Stratton junction (Rat Trap) as SSE (electric company) work at the scene.
One fire crew from Oxfordshire are in attendance but no firefighting action has been necessary at this stage.
It is not yet clear how the power cable came to fall, but the utility pole holding the cable above the main road appears to be bowing into the A419.
Police say the road will be closed for several hours.
