Times Best Law Firms listing: Lower Thames Crossing – case study

This year, TLT once again featured among The Times 'Best Law Firms', commended for 'Administrative & Public Law' and 'Planning'. In this Q&A, Planning Partner and Co-Head of the firm’s Infrastructure sector, Tom Henderson, reflects on our work with National Highways advising on the nationally significant infrastructure project Lower Thames Crossing – an outstanding example of our work at the intersection of Planning, Infrastructure and Public Law.

Q: Tom – can you give us some initial background – what is the Lower Thames Crossing (LTC) and why is it so important?

A: The Lower Thames Crossing is one of the UK’s largest nationally significant infrastructure projects (NSIPs). It consists of a new road linking Kent and Essex via twin tunnels beneath the River Thames, which will help to reduce pressure on the heavily congested Dartford Crossing – currently the only road crossing of the Thames east of London.  

The LTC is designed to almost double road capacity east of London, improve journey reliability, support economic growth and create a more resilient route for freight and logistics. The scheme is also expected to deliver significant environmental and community benefits, including new green spaces, walking and cycling routes and extensive habitat creation. When complete, it will be approximately 14.3 miles long, with 2.6 miles of this in two tunnels under the Thames – making them the longest road tunnels in the UK.

Q: What was our role in the process?

A: We have worked with National Highways from the inception of the LTC project and helped guide it through every stage of the Development Consent Order (DCO) process.  Our role was to provide strategic planning, environmental and public law advice. Development consent was granted in 2025 without legal challenge, marking a major milestone for both National Highways and the wider project team.

Throughout the DCO stage of the project, our remit included:  

• Advising on the overall DCO strategy and supporting documentation;

• Reviewing key application materials, including the Planning Statement and Environmental Impact Assessment.

• Representing National Highways at hearings during the examination process.

• Supporting negotiations with statutory undertakers and other affected third parties.

• Advising on compulsory acquisition powers and legal risk management.

• Coordinating legal workstreams and supported delivery through dedicated legal project management.

We are now advising on the implementation stage of the project, including land assembly, secondary consenting and the transfer of the project – alongside the existing Dartford Crossings – into a "regulated asset base" delivery model.  This will involve a licensed private sector body owning and operating the crossings (including completing construction of LTC), regulated by the Office of Rail and and Road.  The model requires deployment of new primary legislation, the Highways (Financing) Bill, which is currently working its way through Parliament and which we are also supporting on.

Q: How did the team manage a DCO project of this scale?

A: The DCO stage of the project was one of the most significant we have handled, involving more than 20 planning lawyers at its most intensive stage. Such a large team required dedicated legal project management to coordinate multiple workstreams, monitor risks and maintain progress against key milestones was vital.  

National Highways and the LTC project team remained at the centre of decision-making, with swift access to our specialist legal support whenever they needed it. Regular reporting, knowledge-sharing and resource planning were the keys to maintaining consistency throughout a project that spanned many years.

Q: Did the project establish any new approaches or precedents?

A: The scale of the project required innovative approaches to both case-making and statutory drafting and the Development Consent Order included a number of innovative drafting solutions that have subsequently become recognised examples of good practice within the DCO sector – demonstrative of our “first of a kind” thinking. For example, the DCO contains provisions authorising the direct vesting of land into a third-party statutory undertaker directly, which represents a potentially significant time and cost saving at the delivery stage of the Project. We also created the first legally stakeholder commitments register to be legally secured by a DCO, avoiding the need for third parties to spend money negotiating costly legal agreements.

Our team also played a significant role in developing the project's approach to environmental issues, including carbon emissions, an increasingly important consideration for major infrastructure projects, in line with the UK's net zero ambitions.  The project has the first legally binding commitments on net zero construction stage emissions.

Q: What does this matter say about TLT's Planning and Public Law expertise?

A: I think that it really highlights our ability to advise on complex projects which sit at the intersection of planning, infrastructure and public law. Our planning lawyers have extensive experience advising on NSIPs, combining deep knowledge of the Development Consent Order regime with an understanding of the wider environmental, regulatory and stakeholder issues that shape major developments. In this case, this meant helping National Highways navigate a highly complex consenting process, providing strategic advice and practical support throughout the project.

Major infrastructure projects operate within a complex public law environment, where decisions must withstand significant scrutiny and where legal, regulatory and policy considerations are closely intertwined. Bringing this expertise together with the firm’s planning capabilities enabled us to provide joined-up advice across the project and support National Highways through the challenges associated with delivering nationally significant infrastructure.

It is this combination of specialist expertise, collaboration and experience on high-profile projects that distinguishes our approach. The Lower Thames Crossing is a strong example of the calibre of work being delivered across both Planning and Administrative & Public Law and demonstrates why we continue to be recognised for our expertise.

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