HS2 Faces Legal Setback as Court of Appeal Rules Bromford Tunnel Extension Needs Separate Planning Approval

HS2 Ltd has suffered a significant legal defeat after the Court of Appeal ruled that the extension of the Bromford Tunnel falls outside the planning powers granted by the High Speed Rail Act, requiring separate planning consent following an environmental assessment.

HS2 Ltd has been dealt a major legal setback after the Court of Appeal ruled that a key design change to the Bromford Tunnel extension does not benefit from the planning powers granted under the High Speed Rail (London–West Midlands) Act 2017.

In a unanimous judgment, Lord Justice Holgate, Lady Justice King and Lord Justice Bean upheld an appeal brought by North Warwickshire Borough Council, concluding that while the revised tunnel alignment is authorised under the Act, it cannot rely on the deemed planning permission originally granted by Parliament.

The decision centres on a significant redesign of the railway through Water Orton, where HS2 replaced a section of embankment and viaduct with a much longer twin-bore tunnel.

Originally planned as a 2.9km tunnel, the Bromford Tunnel was extended to approximately 5.8km, allowing the railway to remain underground beneath the eastern edge of Birmingham and reducing its visual impact across surrounding communities.

HS2 argued the revised design would deliver substantial environmental benefits, including a reduction of around 30,000 tonnes of carbon emissions by removing thousands of heavy goods vehicle movements that would otherwise have been required during construction.

Construction of the extension is already well advanced.

The two tunnel boring machines responsible for excavating the extension completed their drives during 2025, with Mary Ann reaching the Washwood Heath portal in May, followed by Elizabeth in October.

Despite recognising the environmental advantages of the revised design, the Court found that the extended tunnel represents a materially different project that had not been assessed through Parliament's original environmental impact process.

Because the changes were considered likely to have significant environmental effects, the judges concluded they required their own Environmental Impact Assessment (EIA) and separate planning approval.

The ruling overturns an earlier High Court judgment that had supported HS2's position following a planning appeal.

The dispute dates back to 2021, when HS2 submitted a Schedule 17 application to North Warwickshire Borough Council seeking approval for works associated with the revised tunnel portal.

The council refused to determine the application, arguing that the extended tunnel fell outside the scope of the powers granted under the 2017 Act and therefore could not be approved through the streamlined planning process available to HS2.

Although a Planning Inspector recommended that HS2's appeal should be dismissed, the case was subsequently called in by the Secretaries of State for Transport and Housing, who approved the application. That decision was later upheld by the High Court before being challenged in the Court of Appeal.

The appeal judges ultimately reached a more nuanced conclusion.

They agreed that the revised works remain authorised under the broad provisions of the HS2 Act but ruled that they do not automatically benefit from the Act's deemed planning permission because Parliament had never assessed the environmental impacts of the extended tunnel.

The judges also rejected HS2's argument that the environmental assessment undertaken during the passage of the Hybrid Bill adequately covered the revised design.

In their judgment, they noted that environmental impacts cannot simply be compared on the basis of whether they are greater or lesser. Different schemes may produce entirely different environmental effects, requiring separate assessment, mitigation measures and planning consideration.

North Warwickshire Borough Council welcomed the outcome, describing the judgment as an important clarification of the legal safeguards surrounding nationally significant infrastructure projects.

Council leader David Wright said the ruling vindicated the authority's longstanding concerns that the environmental consequences of the extended tunnel had not been properly assessed.

He argued the decision demonstrated that even major infrastructure promoters must operate within the legal framework established by Parliament and cannot bypass planning requirements.

The council's Development Management Manager, Erica Levy, said the authority now intends to work with HS2 Ltd and the Department for Transport to ensure the impacts of the revised scheme on residents and businesses around Water Orton are properly understood and mitigated.

While the judgment is unlikely to halt construction of the Bromford Tunnel itself, it represents another significant legal and procedural challenge for HS2, reinforcing the importance of environmental assessment and planning compliance even where engineering changes are intended to deliver wider environmental benefits.