The UK government has allocated an additional £891m ($1.17bn) in public funding for the Lower Thames Crossing road-building project.

The UK's Chancellor of the Exchequer Rachel Reeves committed the funding during the recent Autumn Budget announcement.

The funding means the work is now scheduled to begin next year, and that private investment can move forward, said National Highways. Formal market engagement will launch next year.

Set to open in the early 2030s, the  planned Lower Thames Crossing project aims to address traffic buildup by diverting more than 10 million vehicles per year away from Dartford.

The scheme would nearly double the capacity for road travel across the Thames East of London, introducing three new lanes going each way, said National Highways.

It will connect Tilbury in Essex with Gravesend in Kent through two parallel tunnels beneath the River Thames, forming what aims to be the UK’s longest road tunnel.

The construction work is scheduled to start in 2026, linking the A2 and M2 in Kent with the A13 and M25 in Thurrock over a distance of 23km, 4.2km of which will be underground.

The project aims to improve connections between ports in South East England and regions such as the Midlands and Northern England, as well as strengthen capacity across existing road networks.

The government first proposed plans for a second crossing between Essex and Kent in 2009, with £1.2bn spent on planning since then.

In March this year, authorities granted official approval for construction to proceed.

Lower Thames Crossing executive director Matt Palmer said: “The funding from government gives us the green light to start building the Lower Thames Crossing next year and puts it on track to open in the early 2030s.

“The project will be built by local people and businesses, and leave a legacy of jobs and skills across the region. It’s the first of a new generation of projects that will tackle congestion and drive economic growth, whilst redrawing the blueprint for low-carbon construction.”