Two full-time cleaners are now employed for the motorways

The Highways Agency said it was now having to employ two full-time cleaners to deal with the issue along routes including the M6, M5, M40 and M42.

Agency staff have urged motorists not to dump waste along the side of the roads and warned it could be a potential driving hazard.

A spokesman said it cost �500,000 a year to clean up the region's roads.