A two-vehicle crash is causing heavy delays on the southbound stretch of the A1(M) between Stevenage and Welwyn.
The collision happened just past Junction 7 for Stevenage at about 4.40pm.
There is currently debris on the road and two ambulance crews are at the scene treating one female patient.
The extent of her injuries, or if anyone else was injured, are not known but are not believed to be serious.
Police are at the scene and believe that both vehicles will require recovery. They are therefore advising people to avoid the area if possible.
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