Update - 22:30 Road now open.
National Highway have said the A66 is currently closed westbound between the A1 J53 (Scotch Corner) and the A67 (Bowes) due to a collision involving 2 cars.
All emergency services are in attendance along with National Highways Traffic Officers with the road expected to remain closed for the next few hours.
Road users travelling across the Pennines are advised to plan ahead and consider alternate routes such as the A69.