Royal & SunAlliance is to hang out to dry cowboy drainage companies by producing Best Practice guidelines.

The insurer has joined forces with the environmental consultancy WRc to produce guidelines for the 200 major drainage companies that maintain and repair 200,000 miles of domestic drains.

“We believe that up to 10,000 miles of drainage may be affected by tree root activity every year and, as a result, RSA alone spends some £20m annually on drainage works,” said Tony Boobier, subsidence manager.

“The UK drainage industry is not as sophisticated as in many parts of Europe and our aim with WRc is to develop a new breed of drainage specialist and combat the cowboys.

“By having Best Practice guidelines, drainage specialists will carry out repairs to new leading standards and improve workmanship, materials and customer care.”