The Welsh Ministers (First Minister Eluned Morgan) approved the planning application submitted by Cardiff Parkway Developments for the construction of Cardiff Parkway railway station and business district in St Mellons, Cardiff (the Decision), despite its location on the Rumney and Peterstone SSSI. A crucial finding was that, while part of a Site of Special Scientific Interest (SSSI) would be damaged and a local Site of Importance for Nature conservation (SINC) would be lost in its entirety, this harm was “outweighed by” the strategic benefits of the scheme. It illustrates how even a development plan that encroaches on a protected habitats can be approved if it demonstrably advances sustainable transport and development goals and embeds strong environmental safeguards.
Our previous article, available here: Biodiversity versus Cardiff Parkway – Capital Law, discusses the proposed plans for the development of Cardiff Parkway.
Stephen Sykes, Fern Dempsey, and Olivia James from our Environmental Disputes team report below.
Background and considerations
The Cardiff Parkway application (the Application) was met with controversy due to its potential impact on existing infrastructure in St Mellons and on biodiversity within SSSI, alongside the Severn Estuary. This unique landscape, reclaimed from the sea over 2,000 years ago, holds significant ecological and cultural value.
The primary objective of the Application was to improve transportation in east Cardiff, a region currently underserved by public transport, where bus journeys to the city centre often take up to an hour.
In light of the significant environmental and community implications, the Welsh Ministers called in the Application for detailed consideration on 20 October 2022. Public hearings were held in July 2023 and January 2024 to thoroughly assess the proposal’s impact on the SSSI and the wider St Mellons/Cardiff community.
Step-Wise Approach
Planning Policy Wales (PPW, 2021/2023) requires developments to provide a “net benefit” (net gain) for biodiversity – meaning that projects must leave nature in a better state than before. (Wales’ net benefit approach is strikingly different to England’s 10% BNG target driven by a BNG metric. Wales has not set a fixed biodiversity gain percentage – e.g., it is up to Welsh Local Authorities to judge an appropriate gain).
Under the Environment (Wales) Act 2016, public bodies (including planners) must “maintain and enhance biodiversity and promote ecosystem resilience”. The Inspector’s report and decision letter carefully apply this duty: they note that the scheme will damage qualifying SSSI habitat, but that it also includes “nature-based solutions to secure sustainable growth and ecological connectivity” – essentially restoring and improving ditches, reedbeds and woodlands in the Gwent Levels.
Recent Welsh policy (effective Nov 2023) has strengthened SSSI protection. Chapter 6 of PPW now makes development in or affecting an SSSI “unacceptable as a matter of principle” except in “wholly exceptional” circumstances. It also formalises a step-wise approach, in line with PPW 6.4.11, ensuring that adverse environmental effects are sequentially avoided, minimised, mitigated, and, as a last resort, compensated for.
The Decision acknowledges that the development will result in unavoidable environmental effects, including the loss of approximately 8% of part of the SSSI and the partial destruction of the Marshfield Site of Importance for Nature Conservation (“SINC”). However, these impacts were permitted under the designation of “wholly exceptional circumstances”, as set out in national planning policy and justified by significant public benefits.
To address these impacts, a series of mitigation and compensation measures were secured through a Section 106 agreement. Notable environmental enhancements include:
- The creation of 4.4km of new drainage ditches to replace 3.9km affected by the development, resulting in a net 10% gain in biodiversity.
- On-site and off-site habitat enhancement, with a focus on maintaining and improving wetland conditions and species diversity.
- A commitment to long-term ecological monitoring and adaptive management to ensure the effectiveness of compensation measures over time.
The decision and its justification
In her ruling, the First Minister, Eluned Morgan, endorsed the planning inspector’s conclusions and highlighted the wides public benefits of the scheme, determining that these outweighed the ecological concerns – particularly in light of the mitigation and compensation measures secured throughout the planning process. The decision letter can be found here.
The final consent includes detailed conditions and a Section 106 Agreement requiring:
- A Biodiversity Enhancement / Green Infrastructure Plan (SGIMS) to be implemented across the site (on and off the railway corridor) . This covers creation of wetlands, reens, woodland and buffer habitats.
- A water-quality monitoring and management strategy, mammal crossing designs, hedge and tree planting schemes, and other ecology safeguards. (Condition 30 in the decision for example requires a “biodiversity enhancement plan” and its full implementation).
- Off-site habitat works (e.g. managing land for new SINC status) to compensate for the full impact on protected areas . In particular, a field south of the railway will be managed to achieve “future SINC status” in lieu of the lost Marshfield SINC.
- Long-term monitoring and reporting on ecological outcomes, including flood attenuation and surface water quality, to ensure the net biodiversity benefits are delivered. (The conditions require monitoring of wetlands and wildlife features as part of the approved management scheme.)
Key justifications underpinning the approval included:
- Economic regeneration and job creation: The development is expected to generate over 3,000 jobs, significantly benefiting an area ranked among the 10% most deprived in Wales. This was regarded as a substantial factor in the public interest.
- Sustainable transport: The creation of a sustainable transport hub is intended to improve connectivity and reducing reliance on car travel – aligning with national climate action and transport policy objectives.
- Biodiversity measures: Environmental compensation measures secured through a section 106 agreement include both on and off-site habitat enhancements aimed to deliver a net gain for biodiversity and mitigate environmental impacts on the SSSI.
- Alignment with planning policy: Consistency with Cardiff’s Local Development Plan, supporting strategic growth.
- Green infrastructure and placemaking: The scheme was found to incorporate Green Infrastructure principles and aligning with Placemaking Wales Charter objectives, such as sustainable design, community connectivity and promoting well-being through access to open spaces.
- Deliverability and phasing safeguards: The decision accounted for phasing safeguards, including the delivery of the railway station alongside the first phase of employment floorspace. The proposed phasing approach ensures that occupation thresholds are tied to progress on station delivery, mitigating risks of non-completion.
Conclusions
The Cardiff Parkway approval is a landmark case in Welsh planning.
For developers and landowners interested in natural capital and BNG, the message is clear: biodiversity mitigation is a very important consideration which must be considered with great care. For LPAs and consultants, the decision reinforces the need for rigorous habitat plans and monitoring to meet the statutory net benefit duty.
The approval of Cardiff Parkway demonstrates the tangible impact that evolving local and national policy can have on planning proposals during the period of their development. It is no longer satisfactory for developers to merely mitigate biodiversity loss – as policy is increasingly geared towards conservation, enhancement and measurable ecological gain.
Whether through England’s statutory Biodiversity Net Gain framework or Wales’s proposed Net Benefit to Biodiversity, the regulatory direction is clear; developers are expected to take a proactive, demonstrable approach to safeguarding and improving biodiversity as a core component of planning.
As environmental law and planning policy continue to evolve, these frameworks are likely to give rise to new challenges – particularly where interpretations of biodiversity metrics or ecological baselines are contested.
How can we help?
If you would like advice on how environmental law and policy might affect you and your developments, please contact our Environmental Disputes team.
