Insurers face millions of pounds worth of claims over the next 15 years due to faulty cement being used to build motorway bridges across the south of England.

Market sources said that insurers would be hit by potential claims ranging from personal injury to business interruption, after Lafarge Cement UK admitted that cement supplied by its plant at Westbury in Wiltshire was defective.

Between 2002 and 2004, the cement supplied to some of the largest road builders was contaminated due to the actions of "rogue staff" who misreported levels of alkali in the cement supplied.

The worst affected motorways include the M4 in Wiltshire and M27 in Hampshire.