Motorists warned of long delays as M25 to shut for roadworks

National Highways will work to widen the roads and demolish a bridge as part of a £317m project for the M25. Photograph: Dan Chung/The Guardian

Drivers have been warned of unprecedented traffic jams with the first planned full closure of part of Britain’s busiest motorway, the M25, in March.

A five-mile stretch of the London orbital motorway will be shut for an entire weekend from late 15 March, affecting the journeys of an estimated 200,000 vehicles.