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Background

Sioned Davies

Call: 2019

"Sioned is a rising star; she is meticulous in her preparation and has an excellent presentation style. Her written opinions are also of the highest quality. She is a go-to junior barrister"

Sioned Davies - Legal 500 2025 Rising Star

"Sioned is meticulous in her preparation and has an excellent presentation style. Her written opinions are also of the highest quality. She is a very bright junior with a finger on the pulse of the latest legal and commercially relevant developments"

Legal 500 2025 - Rising star

" Sioned is a pleasure to work with. Her written skills are fantastic and she is a great advocate - solicitors always enjoy having her on the team."

Legal 500 2025 - Leading Junior

"She is also very approachable, very much part of the team and happy to get stuck in"

Planning Magazine 2024

"Only called to the bar in 2019, Sioned Davies has developed a varied practice since joining No5 Barristers Chambers in the following year. This has included acting in several solar, minerals and residential appeals as sole counsel, as well as advising on such schemes. This expertise includes environmental law issues, like biodiversity net gain and natural capital, where one leading planning solicitor notes that Davies is “clearly on top of the brief”. In addition, the Welsh-born barrister has a “particular expertise” on advising on planning matters in the principality, says a consultant. She describes as “phenomenal” Davies’ ability to take “complex, or quite diverse matters, and distill them into very clear and very distinct advice, particularly for somebody at her level"

Planning Magazine 2024

Sioned Davies has gained a broad range of experience across planning and environmental law in both England and Wales. Sioned advises a wide range of clients including residential, commercial, energy, minerals and logistics developers, public bodies including the Welsh Ministers, and other interested parties.

She has appeared led and unled in hearings, at inquiries and in the courts (Magistrates, County Court, High Court, and Court of Appeal). She regularly appears as sole or junior counsel in significant multi-week inquiries, including on residential, renewable energy, or minerals development.

Sioned is recognised as a leading junior under 35 (ranking in 3rd in 2024) by Planning Magazine. She has also been recognised in the overall top 20 junior barristers in this area of law (2023, 2024) and overall, for specialist commercial planning work (2023). She is also ranked as a Leading Junior by Legal 500 (London), and as a “Rising Star” (Midlands Circuit and Wales and Chester Circuit)

Expertise

Planning

Energy

Sioned has worked on several renewable energy matters, including solar, offshore wind and tidal schemes.

Recent instructions include:

  • Promoting a cross-boundary application for 30MW of solar arrays including battery storage in Babergh and Mid Suffolk. This was successful including the recovery of costs (junior to Thea Osmund-Smith).
  • Acting for a Local Planning Authority successfully objecting to a solar scheme at Berrington, Shrewsbury (30MW) (unled).
  • Acting for a Local Planning Authority objecting to a scheme at Kemberton, Telford, Shropshire (22MW) (unled).
  • Advising on legal issues arising from the consenting of the largest consented tidal energy scheme in the UK (240 MW). This provides a “plug and play” facility for commercial tidal energy operators.
  • Advising on legal aspects of several offshore wind projects, including habitat assessment and environmental impact assessment, and on the necessary supporting infrastructure including harbour revision orders.
  • Resisting a 30MW solar farm application by the Rule 6 Party who are tenant farmers in North Yorkshire (unled)

    Highways

    Sioned has experience in advising on highways matters. This includes the assessment of evidence and appearing at hearings dealing with specialist highway issues.

    Current and recent instructions include:

    • Acting for a large logistics developer making submissions about the status of the adoption of roads in the context of s.78 planning appeal.
    • Advisory work for National Highways in a planning appeal.
    • Acting for a Local Authority making stopping up applications in the magistrates’ court.

      Planning Judicial and Statutory Reviews

      Sioned regularly advises on the merits of bringing a High Court challenge, and on the defence of such claims.

      Recent instructions include:

      • Acting as junior counsel defending the grant of planning permission in the High Court on behalf of the promoters and developers of a site with consent for over 2500 houses in Worcestershire (junior to Peter Goatley KC) – Bentley Pauncefoot Parish Council v Redditch Borough Council & Anor [2023] EWHC 456 (Admin)
      • Acting as junior counsel defending the grant of planning permission for over 2200 houses on behalf of the Local Planning Authority. The challenge related to the provision of NHS contributions (junior to Hugh Richards) – Worcestershire Acute NHS Trust v Malvern Hills District Council & Ors [2023] EWHC 1995 (Admin)
      • Defending the grant of planning permission for a crematorium in the Green Belt (junior to Peter Goatley KC) – Wathen-Fayed v SSLUHC [2023] EWHC 92 (Admin). Currently on appeal to the Court of Appeal.
      • Challenging the Screening Direction of the Secretary of State concerning a point of interpretation of the EIA Regulations – BW Farms Ltd v SSLUHC [2024] EWHC 217 (Admin) (unled)
      • Acting for the Interested Party in a Statutory Review in respect of a challenge to an Inspector’s decision to refuse planning permission for a quarry – NRS Saredon Aggregates Ltd v SSLUHC [2023] EWHC 2795 (Admin) (unled)
      • Acting for the Claimant in relation to a Judicial Review of a Decision of NRW to grant consent for a commercial operator on the River Wye – Townley v NRW [2021] EWHC 2391 (Admin) (unled)

      Sioned also has experience in seeking injunctive relief in the higher courts on her own and led. She was junior counsel in obtaining a “Route Wide” Injunction for trespassers on the HS2 line (Junior to Richard Kimblin KC)

      Major Infrastructure

      Sioned has gained broad experience of infrastructure planning and consenting regimes in both England and Wales.

      Throughout her pupillage, she gained experience of challenges to major infrastructure projects, including offshore decommissioning projects in the North of England, to HS2, Drax Power Station, and the North London Heat and Power Project.

      • Recent instructions include:Advising on a Transport and Works Act Order on the development of a commercial tidal energy demonstration zone.
      • Early advice on compulsory purchase and compensation relating to the development of HS2.
      • Advising on Permitted Development rights in relation to ports for EV import/export.
      • Seeking injunctive against persons unknown and several named defendants in relation to HS2.

        Minerals & Waste

        Sioned has experience acting for promoters and objectors of mineral and waste projects, both in inquiries and in courts.

        Recent experience has included:

        • Acting as junior counsel to Richard Kimblin KC in an application for a sand and gravel quarry in the Dorset AONB.
        • Acting as junior counsel to Richard Kimblin KC promoting a major quarry in South Wales for high PSV gritstone. The application was a called-in inquiry into the Welsh Ministers and was successful including in the recovery of costs.
        • Advising on the evidence base behind the release of a site constrained by a waste designation through a Local Plan process in West London.
        • Reviewing climate change assessments (Scope 1, 2 and 3 emissions), and environmental assessment.
        • Acting for a Rule 6 Party in successfully resisting the grant of planning permission for minerals development in Worcestershire following a two-week inquiry in Worcestershire.
        • Acting as junior counsel to Peter Goatley KC in a High Court challenge brought by a Parish Council to the grant of planning permission to the grant of a s.73 permission for the importation of inert material.
        • Advising interested parties in relation to a Development of National Significance, a concrete crushing facility and new power plant.

        Plan-making

        Sioned advises on allocations and prospects of bringing forward development through Plans. She is able to assist in making representations at the plan-making stage for all stakeholders. She is familiar with scrutinising the evidence base required to promote or challenge sites in a Local Plan, including Neighbourhood Plans. She also has experience of legal challenges to plans.

        Recent instructions include:

        • Assisting the Home Builders Federation (HBF) in relation to the evidence in a Local Plan and the allocation of residential development sites.
        • Assisting a LPA with defending a legal challenge to a Local Plan.
        • Advising on the statutory powers associated with the adoption of a Local Plan.

          Planning Appeals

          Sioned has considerable experience in representing all stakeholders at planning appeals including both as sole and junior counsel.

           

          This includes acting for a wide range of clients including residential, commercial, energy and minerals developers, public bodies and other interested parties.

           

          This also involves a full range of issues including need (including housing and supply) heritage, landscape, flood risk, highways, ecology, landscape, and carbon.

          Recent instructions include:

          • Acting for Westminster City Council in the two-week inquiry into the Secretary of State’s call-in of the application for the redevelopment of 458 Oxford Street, M&S flagship store. Key issues include heritage and sustainability assessment (unled).
          • Acting for Tritax Symmetry at Symmetry Park for employment development including complex archaeology, heritage and highways issues (unled).
          • Acting for a Local Planning Authority in resisting the development of playing fields for 33 residential dwellings on the Wirral (unled) (ongoing)
          • Successfully acting for a Local Planning Authority in resisting the development of 44 units of retirement living housing (unled)
          • Acting as Junior Counsel in a cojoined planning inquiry concerning rival crematoria developers in the Green Belt (junior to Peter Goatley KC).
          • Successfully acting in a 9-day inquiry for 700 dwellings and commercial space including the recovery of costs (junior to Christopher Young KC).
          • Successfully acting in a 9-day inquiry for mixed-use development for 216 homes, 1600 square metres of commercial space in London (junior to Christopher Young KC).
          • Successfully acting as junior counsel promoting a major quarry in South Wales. The application was called into the Welsh Ministers and included the recovery of costs (junior to Richard Kimblin KC).
          • Successfully acting in a two-week inquiry for the grant of a recreational surf lagoon in the Green Belt (junior to Paul Cairnes KC).
          • Successfully acting for a Rule 6 Party in resisting the grant of planning permission in Worcestershire for minerals development.

            Planning Enforcement

            Sioned has experience in planning enforcement. This includes advising on the evidence, investigation and service of enforcement notices and acting for appellants at hearings and inquiries.

            Recent instructions include:

            • Acting for the Police as a Rule 6 Party in relation to a two-week enforcement inquiry concerning the Zig Zag Building, Glastonbury.
            • Acting for Local Planning Authority in bringing planning injunctions in the High Court and the County Court relating to unlawful development in the Green Belt.
            • Acting for a Local Authority in respect of an appeal of a statutory nuisance case.

            Residential

            Sioned has considerable experience in advising on residential development, both in her own capacity and as part of a team.

            Sioned has appeared in a wide range of successful residential appeals including across London, the south east, south west, midlands and Wales, and in areas with particular planning constraints including in Green Belt and AONB.

            Key issues have included housing land supply/need, heritage, landscape, affordable housing, drop-in permissions, self-build/custom build, ecology and biodiversity net gain, and planning obligations.

            In her own right, she has advised several housebuilders on different aspects of the development life cycle including Bloor, St Modwen, BDW, Redrow and Greymoor Homes.

            Current and recent instructions include:

            • Promoting the development of 42 dwellings in Mole Valley (unled) Heritage is a key issue.
            • Promoting the development of 125 dwellings in the Green Belt, Hertfordshire (junior to Christopher Young KC).
            • Acting for a Local Planning Authority in resisting the development of playing fields for 33 dwellings on the Wirral (unled).
            • Successfully acting for a Local Planning Authority in resisting the development of 44 units of retirement living housing on the Wirral (unled).
            • Successfully resisting the development of 30 dwellings together with Howard Leithead in Malvern Hills. Sioned dealt with the housing land supply position.
            • Successfully acting in a 9-day inquiry for 700 dwellings and commercial space including the recovery of costs, in Coventry (junior to Christopher Young KC).
            • Successfully acting in a 9-day inquiry for mixed-use development for 216 homes, 1600 square metres of commercial space in Enfield, London (junior to Christopher Young KC).
            • Successfully acting as junior counsel defending the grant of planning permission in the High Court on behalf of the promoters and developers of a site which was granted planning permission for over 2500 houses in Worcestershire (junior to Peter Goatley KC) – Bentley Pauncefoot Parish Council v Redditch Borough Council & Anor [2023] EWHC 456 (Admin).
            • Successfully acting as junior counsel defending the grant of planning permission on behalf of the local planning authority for the over 2200 houses. The challenge relates to the provision of NHS contributions (junior to Hugh Richards) – Worcestershire Acute NHS Trust v Malvern Hills District Council & Ors [2023] EWHC 1995 (Admin).
            • Acting as junior counsel on a judicial review relating to the redevelopment of Bristol Zoo Gardens for 196 dwellings (junior to Peter Goatley KC)
            • Advising on strategy for the development of 79 dwellings on a brownfield site. Permission was ultimately granted.
            • Acting for the LPA in an inquiry for the development of up to 130 dwellings in Wychavon (unled)
            • Acting for the LPA in an inquiry for the development of 55 dwellings in Malvern Hills (unled).

              Biodiversity Net Gain

              Sioned advises on issues resulting from the introduction of mandatory Biodiversity Net Gain (BNG). She advises developers and public bodies on the practicalities of BNG and as part of a wider natural capital offering.

              She is available for talks and training on this rapidly developing area of law.

              Environment

              Climate

              Sioned regularly advises all stakeholders about risks and opportunities relating to climate change. This includes both mitigation and adaptation.

              Her experience has encompassed advising on the generation of policies, EIA, SEA, Whole Life Carbon Assessment (WLCA), renewable energy infrastructure and climate-related legal challenges. She also has experience in advising on flooding issues including the application of the sequential test.

              Recent instructions have included:

              • Advising developers on the assessment of Scope 1, 2 and 3 emissions as part of the EIA.
              • Inquiries involving WLCA as a key issue – including 458 Oxford Street, Marks and Spencer’s flagship store and Lea Halls, Luton.
              • Advising on and the deployment of renewable energy schemes (solar and tidal).
              • During pupillage, she also assisted in some research in the early stages of climate-related legal challenges to the development of the UK Emissions Trading Scheme – R(Elliot-Smith) v SSBEIS [2021] EWHC 1633 (Admin) and to Drax Power Station R (Client Earth) v SSBEIS [2021] EWCA 43.

              Prior to coming to the Bar, Sioned was Head of the Secretariat to the Climate Law and Governance Initiative at COP 24 in Katowice, Poland. This event brought together lawyers in the global climate discussion including from states, the World Bank, Green Climate Fund and leading law firms.

              Environmental Assessment

              Sioned has advised on contentious aspects of environmental assessment (EIA and SEA) for promoters and assessors of various types of development.

              Environmental Regulation and Prosecution

              Sioned has undertaken a number of environmental prosecutions in respect of environmental regulatory matters. This has included an assessment of detailed expert evidence and advice on settlement.

              Nuisance

              Sioned has appeared in several statutory nuisance matters. This has included prosecuting and defending (concerning individuals, Local Authorities, residential and commercial developers). She is familiar with the assessment of detailed expert evidence including best practicable means and advising on settlement.

              Protected Habitats and Species

              Sioned regularly advises on protected habitats and species and the implications for all parties. She has advised developers regularly on how to navigate this regulatory landscape including in respect of phosphates and nitrates issues in England and Wales.

              Recent instructions have included:

              • Advising several residential developers in respect of nutrient neutrality and phosphate issues and on proposed solutions across several different schemes.

              • Advising several commercial farming operations on navigating the impacts of phosphates and nitrates regulation for poultry development in respect of protected rivers.

              • Advising on protected habitats and species in respect of marine licensing for offshore wind and tidal energy.

              Agriculture

              Sioned has gained considerable experience advising on schemes for all manner of renewable and agricultural installations, ranging from supporting renewable energy infrastructure on farm to anaerobic digestion schemes and intensive livestock installations.

              Related News, Resources and Events

              News


              LPA Seminar

              Thank you to all who attended the Local Planning Authority Seminar Yesterday. We hope it was both informative and enjoyable for you all.

              Podcasts


              The Planning Podcast Episode 48 – Eia and Green House Gases after Finch – a Short Practical Explainer

              Finch is a Supreme Court judgment which has been long awaited. It deals with the effects of development which are ’downstream’. Many practitioners want to know…

              View all related news

                      

              "Advocacy at public inquiry is real strength - Sioned displays excellent qualities in terms of her prep, thoroughness, understanding of the case and relevant case law and precedents and communication skills."


              • Kate Bertram Prize for academic distinction (University of Cambridge) for top-rated departmental research paper.
              • John Frederic Whitehouse Award for highest marked law dissertation (UCL)
              • Bentham Award for high academic achievement (UCL)
              • UKELA
              • Planning and Environmental Bar Association
              • Administrative Law Bar Association
              • Young Compulsory Purchase Association
              • Young National Infrastructure Planning Association

               

              • Welsh Government Junior Barrister Public Law Scheme
              • Chair of National Agricultural Youth Charity (under 21)
              • Nuffield Scholar (2025)
              • BPP Law School – Bar Professional Training Course – Very Competent (2019)
              • University of Cambridge – Environmental Law and Policy (MPhil) – First Class Honours (2018)
              • University College London (UCL) – Law (LLB) – First Class Honours (2017)
              • English
              • Welsh (fluent)
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              Related News, Resources and Events

              News


              LPA Seminar

              Thank you to all who attended the Local Planning Authority Seminar Yesterday. We hope it was both informative and enjoyable for you all.

              Podcasts


              The Planning Podcast Episode 48 – Eia and Green House Gases after Finch – a Short Practical Explainer

              Finch is a Supreme Court judgment which has been long awaited. It deals with the effects of development which are ’downstream’. Many practitioners want to know…

              View all related news

              Clerk Team

              Marc Forrest-Thomas

              Practice Manager, Planning & Environment

              marct@no5.com

              Natasha Clark

              Planning and Environment Clerk

              natashac@no5.com

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