British Waterways is paying £2.5M a year to repair damage to historic humpback bridges caused by cars.
The company said money that should be spent on maintaining its 2,000 miles of rivers and canals is being diverted to repairing the bridges, with many drivers leaving the scene without reporting the incident.
British Waterways maintains 1,800 bridges, some 200 years old, but it estimates that at least two are struck each week.
British Waterways head of heritage Nigel Crowe said: “Whenever you go over a humpback bridge in Britain you are likely to be going over a canal. Often officially listed as being of special architectural or historical significance, these bridges have to be painstakingly repaired at considerable cost.
“We’re working with the County Surveyors’ Society and local authorities to improve signage and road markings, but, frankly, if motorists just slowed down a bit and took more care and attention then we’d not be defacing our heritage in this way on a day-to-day basis.”
Humpback bridges were built using traditional materials such as lime mortar and locally sourced stone or brick. Damaged sections of bridges are replaced with like-for-like materials, using skills passed down over many generations.