The contraflow has been in place for a month

Automatic speed cameras have recorded six drivers doing 75mph in the 40mph zone between Buckfastleigh and Ashburton on the A38 in the past month.

Contractors on the five-mile contraflow said they fear for their safety.

Police are not revealing total figures for speeding, but warn they will press for increased penalties for drivers who break the law.

Inspector David Pryce said: "People should realise what the speed limits are and they should slow down.

"The dangers they can cause to other motorists as well as the people working there are huge."