The Lower Thames Crossing
A new tolled crossing of the Thames, 14 miles east of Dartford. Construction began in March 2026. Designed to relieve the M25 by taking up to a quarter of Dartford's traffic. Expected opening: early 2030s.
Status
Construction
Started
March 2026
Tunnels
Twin bored, ~4.25km
Capacity
~4 lanes equivalent
Approved
March 2025
Major build phase
2028 onwards
Expected opening
Early 2030s
Distance from Dartford
~14 miles east
Where it goes
The route runs from Shorne in Kent (near the M2 J1) up through twin bored tunnels under the Thames and emerges in South Ockendon, Essex (near M25 J29). Two new sections of dual carriageway link the tunnel mouths to the existing strategic road network. Total length is roughly 14 miles, of which 4.25km is tunnel.
Why it's being built
The Dartford Crossing carries roughly 150,000 vehicles per day against a design capacity of 135,000. Congestion has been the norm for two decades. The Lower Thames Crossing is intended to absorb 20-25% of Dartford's flow once open, restoring some spare capacity at the existing crossing and providing a redundancy route during incidents.
Will it be tolled?
National Highways has not published final pricing. The expectation is that it will be tolled to recover construction costs (the project is one of the most expensive UK road builds ever). It is likely the same Dart Charge or pre-pay infrastructure will handle payment, though that detail has not been confirmed.
What this means for current drivers
For the next several years, nothing changes. Dart Charge prices are set independently of the LTC. The Dartford Crossing will remain the only practical eastern route until the late 2020s at the earliest. The £25 resident pass and the pre-pay account remain the cheapest options for anyone who crosses regularly.
Funding milestones
The development consent order was granted by the Secretary of State on 20 March 2025. £590m of preliminary funding was approved in June 2025, followed by a further £891m in November 2025 to start the major works. Early ground-investigation and infrastructure-preparation contracts began in March 2026. The headline budget remains under public scrutiny.