The government has announced £590m in funding to take forward the long-awaited Lower Thames Crossing.

The finance is part of a £1bn package to enhance and repair run down transport infrastructure and futureproof England’s road network.

The Structures Fund will inject cash into repairing run down bridges, decaying flyovers and worn out tunnels across Britain, and ensure other transport infrastructure is more resilient to extreme weather events and to the demands of modern transport.

The Lower Thames Crossing will be a new road crossing connecting Kent, Thurrock and Essex. Approximately 14.5 miles (23km) in length, it will connect to the existing road network from the A2/M2 to the M25 with two tunnels (one southbound and one northbound) running beneath the River Thames. 

It will ease congestion at Dartford by almost doubling road capacity across the Thames east of London and make tens of millions of journeys quicker, safer and more reliable every year.

The government has announced £590m for the project describing it as the “most significant road building project in a generation” and a “national priority”.

The government will look to bring in private finance and expertise to support this major project.

It also says across Great Britain, approximately 3,000 bridges are currently unable to support the heaviest vehicles, restricting access for agricultural and freight transport in regions, and slowing down journeys. And nationally, the number of bridge collapses has also risen – prompting the funding decision.

These investments come as part of the new 10 Year Infrastructure Strategy, which will be published later this week.

Chancellor Rachel Reeves said: “When it comes to investing in Britain’s renewal, we’re going all in by going up against the painful disruption of closed bridges, crossings and flyovers, and ensure they’re fit to serve working people for decades to come.

“Today’s investment also goes even further and faster to spread growth by providing critical funding to take forward the Lower Thames Crossing – not just boosting connectivity in the South-east, but ensuring a smoother, less congested passage of vital goods from Europe to our regions.

“This is a turning point for our national infrastructure, and we’re backing it with funding to support thousands of jobs and connect communities, delivering on our Plan for Change.”

Transport secretary, Heidi Alexander, added: “We’re finally getting on with the Lower Thames Crossing — a crucial project to drive economic growth, that has been stuck in planning limbo for far too long.

“This project is essential for improving the resilience of a key freight route and is critical to our long term trade with Europe. It will speed up the movement of goods from South-east England to the Midlands and the North, crucial to thousands of jobs and businesses.

“Our structures fund will make long-overdue investments to repair ageing structures across the country, speeding up journeys, restoring pride and delivering our Plan for Change to boost the economy and support regional growth.”

Government will set out more detail about how funding will be allocated shortly. This funding is additional to the funding local authorities will receive for highways maintenance, which will be set out in due course.