Insurers are facing a potential £100m repair bill for drainage problems caused by decaying pitch fibre water pipes, according to drainage specialists Dyno-Rod.

Pitch fibre pipes were widely used during the 1960s housing boom as a cheaper alternative to traditional ceramic pipes.

They were quickly outlawed by building inspectors, after it was discovered they have a limited lifespan and are expensive to repair. But the pitch fibre pipes were used in thousands of homes and are now reaching the end of their life span.

According to Margaret Burke, Royal & Sunalliance claims adviser for Cornwall: "Pitch fibre pipe drainage problems have been increasing steadily over the past few years and they are proving expensive to solve."

Previously, replacing pitch fibre pipes would have meant extensive excavation and replacement, but Dyno-Rod is currently piloting a cheaper repair process that involves relining damaged pipes.