A Government decision on whether to go ahead with a new £9 billion road crossing between Kent and Sussex is due to be announced on Friday.
That is the deadline for whether the 14.3-mile long Lower Thames Crossing will be approved.
Work on the project has been ongoing since 2009, and more than £800 million of taxpayers’ money has been spent on planning.
The proposal is aimed at reducing congestion on the Dartford Crossing with a new motorway-style road.
It would connect the A2 and M2 in Kent to the A13 and M25 in Essex via a 2.6-mile long tunnel under the Thames, which would be the UK’s longest road tunnel.
National Highways says the plan will almost double road capacity across the Thames east of London, describing it as “our most ambitious scheme in 35 years”.
It is aiming to start construction in 2026, with the road opening in 2032.
Thurrock Council in Essex has consistently opposed the project, citing negative economic, social and environmental impacts, but the leader of Kent’s Dartford Borough Council is in favour of the scheme.
Local campaigners Thames Crossing Action Group claim the crossing would be “hugely destructive and harmful”, and a waste of money.
The statutory deadline for a decision on whether to grant a development consent order enabling National Highways to build the road was initially scheduled for June 20, but was delayed due to the general election.
In July, Chancellor Rachel Reeves cancelled the £1.7 billion Stonehenge tunnel scheme and the A27 Arundel bypass project in West Sussex, but did not mention the Lower Thames Crossing.