The M25 London orbital motorway is to be widened to four lanes in each direction under a 25 year private finance deal which it is hoped will dramatically reduce delays on the infamous stretch of road. One of the worst bottlenecks and causes of delay to vehicles is the River Thames Crossing to the east of the capital. Despite the construction of a new four carriageway bridge in 1991, which doubles the previous capacity provided by twin tunnels, the crossing has struggled to meet peak capacity. The proposed M25 widening will add two extra lanes of traffic approaching the crossing and so necessitate construction of an additional four lane bridge.