The UK’s largest road infrastructure project in a generation has been given the green light, as the Secretary of State for Transport grants development consent for the Lower Thames Crossing. The ambitious scheme, connecting Kent, Thurrock, and Essex, is set to ease congestion at the heavily burdened Dartford Crossing.

A Game-Changer for UK Roads

Spanning 23km, the project includes twin tunnels stretching 4.2km beneath the River Thames, providing a vital new link between the A2/M2 and the M25. Designed to tackle severe congestion at Dartford—the busiest river crossing in the country—the Lower Thames Crossing is expected to improve traffic flow and unlock economic growth across the South East.

The estimated cost of the scheme is £9.4bn, with the government exploring private finance options that could push the total to £10.2bn. Already, £1.2bn has been invested, with much of it allocated to the project’s extensive planning and approval process—the largest development consent order (DCO) application ever submitted in the UK.

Following its initial submission in October 2022, the project underwent an exhaustive public examination before receiving approval on 20 March 2024. The decision, which had been delayed multiple times, marks a major milestone in one of the UK’s most complex infrastructure projects.

Construction could begin as early as 2026, with completion expected in the early 2030s. In the meantime, project teams will work closely with local authorities and stakeholders to refine design elements and minimise community and environmental disruption.

A Sustainable Approach to Infrastructure

The Lower Thames Crossing is being positioned as a carbon-neutral construction “pathfinder” project. National Highways aims to significantly cut emissions by up to 70% through the use of low-carbon materials and alternative fuels, such as hydrogen. These sustainability efforts are expected to set a benchmark for future large-scale infrastructure developments, with potential applications in sectors like rail and nuclear energy.

Beyond its transport benefits, the scheme includes major environmental commitments. Plans include the creation of six times more green space than the road itself, planting one million trees, establishing a community woodland, and developing two new public parks with Thames views. Nearly 5km of new and upgraded pathways will also be introduced for walkers, cyclists, and horse riders.

Designed with extensive public consultation, several adjustments have been made to mitigate the impact on local communities and ancient woodlands. These include increasing lane capacity to three in each direction and extending the tunnel length.

Creating Jobs and Boosting the Economy

The project is expected to generate thousands of jobs within the construction sector, with a commitment to recruiting nearly half of the workforce locally. Skills training and employment opportunities will be a key focus, ensuring long-term benefits for communities in the region.

To deliver the project, three main works contracts have been awarded:

• Balfour Beatty will oversee the roads north of the Thames, a contract valued at £1.2bn when awarded in early 2023.
• Skanska has secured the Kent roads contract, initially valued at £450m in summer 2023.
• Bouygues-Murphy JV (BMJV) has been awarded the tunnel and approaches contract, worth £1.34bn in December 2023.

Industry leaders have widely welcomed the approval, calling it a transformative investment in the UK’s infrastructure. Balfour Beatty’s divisional CEO for major projects, highways and ground engineering, Phil Clifton, stated that the project would “unlock capacity, capability, and careers.” Skanska UK’s executive vice president Andrew English added that it would relieve congestion while showcasing innovations in low-carbon construction.

Calls for Funding Clarity

Despite the approval, there are concerns over the project’s funding. The Civil Engineering Contractors Association (CECA) has urged the government to make a swift decision on financing to ensure work can begin without further delays.

However, not everyone supports the scheme. Green Alliance policy adviser Rosie Allen has criticised the government’s approach, arguing that investing in public transport and freight solutions would be a more effective long-term strategy. Campaign group Transport Action Network has described the decision as “economic madness,” questioning the viability of spending up to £16bn on a single road project at a time of budget constraints.

As debates continue, the Lower Thames Crossing remains a landmark infrastructure project with the potential to reshape transport in the South East while setting new standards for sustainability in construction.

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