Gwion Lewis KC > Chambers of David Holland KC and Reuben Taylor KC > London, England > Lawyer Profile

Chambers of David Holland KC and Reuben Taylor KC
Landmark Chambers


Gwion Lewis was called to the Bar in 2005 and specialises in public, planning, environmental, EU and public international law.

He is a member of the Attorney General’s ‘A’ Panel of Junior Counsel, which means that he regularly acts for the UK Government in its most complex cases. Gwion is also a member of the Welsh Government’s ‘A’ Panel of Junior Counsel. He acts regularly for both private and public sector clients at inquiries and has extensive experience of judicial review proceedings and appeals in the higher courts. To date, he has appeared in over 150 inquiries and over 200 substantive judicial reviews.

Gwion has been recommended as a leading junior in all the main independent legal directories for several years. The 2020 versions of these directories describe him as “very punchy and incredibly effective” (Chambers and Partners), “excellent on his feet” and that he “always produces silk-quality work” (Legal 500). He is also said to be “very personable and easy to work with” (Legal 500).

Gwion is based in London but welcomes instructions from all areas of the UK and from international clients. He has experience of advising clients in island jurisdictions, including the Isle of Man and the Channel Islands.

Gwion is the editor of the ‘Wales’ section of the Planning Encyclopedia and appears regularly on television and radio programmes in Wales to analyse legal affairs.


Gwion is Welsh-English bilingual, has good French and is a certified upper-intermediate (B2) Italian speaker (University of Siena, CILS, 2011).


Gwion is a former US-UK Fulbright Scholar and has an LLM from New York University specializing in international human rights, language rights and the interface between law and security. This led to his appointment as a Visiting Scholar at the European University Institute in Florence where he pursued his interest in language rights in EU law.

Before he studied abroad, Gwion was a Scholar of Jesus College, Oxford, where he obtained a BA and a BCL (First Class) in Jurisprudence. When studying for the BCL, he focused on English and French public law, human rights, international dispute settlement and the public international law of the sea. During his time at Oxford, Gwion won several prizes for his performance in examinations on administrative law, public international law, criminal law and Roman law, and was awarded the Welson Prize for the most promising law student at Jesus College. He is also a former winner of the Oxford-Cambridge Intervarsity Mooting Competition and a Bedingfield Scholar of Gray’s Inn.

In 2015, Gwion was awarded the BAFTA Wales award for ‘Best Breakthrough’ for presenting a television documentary on the Welsh language.

In 2017, Gwion was appointed to a 3-year term as a member of the Welsh Government’s Welsh Language Partnership Council. The Council was established under the Welsh Language (Wales) Measure 2011 to advise the Welsh Ministers on matters relating to the Welsh language. Gwion serves as the legal member of the Council.

Also in 2017, Gwion was made an Honorary Fellow of Bangor University, Wales, for services to law.

Lawyer Rankings

London Bar > Immigration (including business immigration)

(2021 Silks)Ranked: Tier 1

Gwion Lewis KC – Landmark ChambersBreath of knowledge. Humility. Honesty. A total team player.

London Bar > Planning

(2021 Silks)Ranked: Tier 1

Gwion Lewis KC –Landmark Chambers ‘Gwion gives clear, considered, accurate advice. He demonstrates dedication to his clients and demonstrable client care. Gwion performs with pragmatism and authenticity.’

London Bar > Energy

(2021 Silks)Ranked: Tier 1

Gwion Lewis KC – Landmark Chambers ‘A lateral thinker who is very well organised and precise in his submissions and his handling of the evidence.’

London Bar > Property litigation

(2021 Silks)Ranked: Tier 1

Gwion Lewis KCLandmark Chambers

London Bar > Administrative law and human rights

(2021 Silks)Ranked: Tier 1

Gwion Lewis KCLandmark Chambers ‘Incredibly easy to work with, provides timely responses, clear advice and confidence that he is a safe pair of hands.’

London Bar > Environment

(2021 Silks)Ranked: Tier 1

Gwion Lewis KCLandmark Chambers ‘Very bright and hardworking with a friendly manner, he provides clear, considered advice with pragmatism and authenticity.’