Lower Thames Crossing

The Lower Thames Crossing is a planned road crossing of the Thames estuary downstream of the Dartford Crossing that links the counties of Kent and Essex, and its proposed approaches. When built it will pass through the districts of Thurrock and Gravesham, supplementing the Dartford route.

First proposed in the late 2000s, the crossing is designed to relieve the pressure on the existing A282 Dartford Crossing. The proposed route would connect the M25 motorway and A13 north of the river to the M2 motorway south of the river. If built, the crossing would have the longest road tunnel in the UK at 2.6 miles (4.2 km). The road number A122 has been reserved for the new road.

The crossing is estimated to cost approximately £9 billion and would take about six years to build following the granting of planning permission. A planning application was submitted in 2020, and withdrawn. A new planning application was submitted in November 2022; the planning process was expected to take 18 months, but this was extended to 4 October 2024, due to the July 2024 general election. A decision to further postpone a decision was announced in October 2024. The crossing was finally approved in March 2025, with construction planned to start in 2026.