Drivers are being told to switch off their engine in queuing traffic amid fears that a sharp rise in roadworks is putting a strain on cars.

Breakdown crews said motorists should stop the engine if they are stuck for more than a minute, to prevent it overheating.

The comments were made as figures suggested that the number of roadworks has risen by more than a fifth in the past year.

A study by LV= Britannia Rescue found that each council in Britain had an average of 139 roadwork schemes at the moment, up from 115 a year ago.

Separate figures showed Highways England, which is responsible for motorways and A roads, completed 1,542 roadwork schemes last year compared with 1,352 in 2013.

A survey of 2,000 motorists found that drivers named the M1 as the most “frustrating” motorway for roadworks, followed by the M6, M25, M5 and M4.

Argyll & Bute council, in western Scotland, had the most roadworks at 837, followed by Gloucestershire (734), Rotherham (656), and Darlington (475).