In a statement the force said: “A double-decker bus has overturned and a number of passengers have sustained injuries.
“Currently we believe that one person has sustained serious injuries.
“We also have over a dozen people who have sustained minor injuries and remain at the scene.”
Police said the South Western Ambulance Service had declared the collision a “major incident” and sent ambulance, patient transport vehicles and the air ambulance to provide support.
Photos shared by DevonLive show the Stagecoach Gold double-decker bus overturned on its side in a field next to the road.