Transport secretary Chris Grayling has ordered councils to stop 'bamboozling' pedestrians by putting up road signs using metric measurements.
He has written to local authorities in England to remind them of guidance that all distances on traffic signs should be in feet, yards and miles.
His instruction comes after campaigners made him aware of a small number of new pedestrian route signs using metric measurements.
The British Weights and Measurements Association said it was becoming concerned that 'unlawful metric pedestrian signs' were 'popping up in town centres and along sea fronts'.
It said they showed 'contempt for the law, and contempt for ordinary people'.
A spokesperson for the association said: 'We're saddened but no longer surprised at the way certain council officials have made it their mission to put their ideology above both common sense and the rule of law.
'Study after study shows that Britons of all ages think of distances in miles. The law mandates their use on road signs.'
Mr Grayling responded: 'I have written to all local authorities reminding them of the clear and consistent signage we expect to be delivered on our highways.
'We think of our travel in miles and miles per hour, whether: flying, cycling, driving, walking or catching a train.'