The plans involve transferring revenues from the existing Dartford Crossing tolls to a new private operator that will build and run the road tunnel beneath the Thames. Under the proposed structure, the operator would retain the income in perpetuity, diverting funds that currently flow directly to the Department for Transport (DfT).
The government argues that allowing the private operator access to Dartford toll revenues will provide crucial upfront cashflow, helping to attract higher private-sector bids for the project. However, transport campaigners warn that the move will leave a significant hole in future transport budgets and reduce funding available for local schemes.
Project Costs Rise Sharply
The Lower Thames Crossing, billed by ministers as “the largest road-building project for a generation”, involves constructing a 14-mile route east of London, including two 2.6-mile tunnels under the river. It is designed to ease congestion at Dartford and improve links between ports and major business hubs.
Since 2017, estimated costs have risen sharply, from £6.8 billion to almost £11 billion.
The project will be delivered using a regulated asset base (RAB) funding model, similar to that used for the Sizewell C nuclear power station. Under this model, private investors receive regulated returns backed by long-term revenue streams.
The government has already committed £3.1 billion in public funds to kick-start construction and attract private investment. At the November Budget, Chancellor Rachel Reeves confirmed a further £891 million, which the Treasury described as the final tranche of government support needed to enable private-sector involvement.
Dartford Toll Revenues Transferred
Newly disclosed correspondence between the DfT and the campaign group Transport Action Network (TAN) shows that ownership and operation of the Dartford Crossing would be transferred to the same private entity responsible for the Lower Thames Crossing.
In a letter to TAN, the DfT said the private operator would be responsible for operating and maintaining both crossings, under regulatory oversight, to ensure consistent service levels.
This arrangement would also give the operator access to net Dartford toll revenues, which totalled £86.7 million in 2023–24 and are expected to rise significantly following a 40 per cent toll increase introduced last September.
Under the Transport Act 2000, Dartford toll income must be used for transport improvements. However, the DfT declined to clarify whether the loss of this revenue has been factored into future departmental budgets or the cost-benefit analysis for the Lower Thames Crossing.
Campaigners Warn of Long-Term Impact
Chris Todd, outgoing director of TAN, said the government was “playing fast and loose with public funds” by pressing ahead without a full business case, which is not expected until 2028.
He warned that over a projected 60-year lifespan, the transfer of toll revenues could amount to more than £7 billion in today’s money, funds he said could otherwise support public transport and local road improvements.
“This project was already poor value before the latest cost increases,” Todd said. “Now it makes no sense at all.”
Government Defends Strategy
The government maintains that combining early construction funding with guaranteed revenue streams will help attract stronger private-sector bids, particularly during the riskiest early phases of the build.
A DfT spokesman said:
“The Lower Thames Crossing is a significant infrastructure project that will improve journeys, boost economic growth and strengthen the resilience of the road network. We have committed £3.1 billion to date to unlock private investment and support long-term operation under a regulated model.”
