Katy Colton

Katy is Head of Politics & Law in Mishcon Private and a Partner specialising in judicial review, public law and administrative law. She is recognised as an expert in complex, high-stakes judicial review claims and strategic public law disputes, particularly challenges to decisions of central government, public bodies and regulators.  Her judicial review practice covers complex challenges across a range of sectors and issues, including education, property, healthcare, human rights and constitutional law.

Katy advises corporations, politicians, individuals, NGOs, charities, families and their businesses.  Her practice focuses on complex public law disputes, high-profile judicial review claims and politically sensitive matters at the intersection of politics and law, including advising on electoral law, campaign finance and lobbying regulations. She also advises on commercial litigation, including standalone commercial disputes as well as matters involving political, regulatory or reputational issues.

Katy acts for claimants and interested parties in the Administrative Court, Court of Appeal, Supreme Court and European Court of Human Rights, as well as advising potential defendants and public bodies on their exposure to judicial review challenge.

Katy has acted in some of the most high-profile judicial review and public law cases in recent years. She acted for Gina Miller in the landmark judicial review claim in the Divisional Court and Supreme Court appeal [R (Miller) v Secretary of State for Exiting the European Union], successfully establishing that the Government could not trigger Article 50 of the Treaty on European Union without an authorising Act of Parliament. She has also advised institutional investors on a multi-party judicial review concerning the Government's leasehold reforms.

Katy is ranked in Chambers UK [2025] and Legal 500 [2025]. Chambers describes her as "absolutely formidable" and "clever, with excellent judgment and trusted by clients to give sound and reliable advice". Legal 500 notes: "Katy Colton is absolutely brilliant. She is an exceptional strategist, extremely bright, and able to explain things clearly to her clients."

Key Experience

Public law and judicial review

• Acting for Gina Miller in the landmark judicial review claim in the Divisional Court and Supreme Court appeal [R (Miller) v Secretary of State for Exiting the European Union], successfully establishing that the Government could not trigger Article 50 of the Treaty on European Union without an authorising Act of Parliament
• Acting for 51 institutional investors in a judicial review challenge of provisions of the Leasehold and Freehold Reform Act, and in a related claim for compensation against the UK before the European Court of Human Rights
• Acting for a clinical research organisation in a challenge to the Medicines and Healthcare products Regulatory Agency
• Advising the Criminal Bar Association on a proposed judicial review claim against the Ministry of Justice concerning criminal defence advocacy fees under legal aid
• Advising on public law matters involving central government decision-making, consultation processes, select committees and public inquiries
• Advising the grandchildren of Ruth Ellis on an application for a conditional pardon

Political litigation and consultancy

• Advising clients on investigations by Parliamentary Standards Commissioners
• Acting on inter-party disputes, including challenges to candidate selection processes
• Acting for the Jewish Labour Movement in relation to the Equality and Human Rights Commission's investigation into antisemitism in the Labour Party
• Acting for Margaret Hodge MP in relation to disciplinary proceedings brought against her by the Labour Party
• Advising on public affairs and law reform campaigns

Commercial litigation

• Advising on a long-running shareholder dispute relating to a family business
• Advising a client in a multi-billion dollar ICSID arbitration against a state involving the alleged expropriation of mining rights and complex issues concerning disputes with state entities
• Successfully negotiating a settlement for several defendants in an £80 million conspiracy to defraud claim involving allegations of fraud and negligence

Career History

Partner, Mishcon de Reya LLP
Managing Associate, Mishcon de Reya LLP
Associate, Mishcon de Reya LLP
Trainee Solicitor, Mishcon de Reya LLP
Secondee to Barack Obama's campaign team, North Carolina - Obama for America
Researcher for David Lammy MP, House of Commons
Legislative intern for Robert Wexler, United States House of Representatives
College of law, GDL, LPC & LLB
University of Leeds, BA (Hons) Politics and Parliamentary Studies

Articles and Publications

• "Lawyer in the news", 28 March 2025, Law Gazette
• "35 Women Under 35: The 'multi-hyphen' millennials to watch", 30 July 2018, The Telegraph
• "Lawyer in the news", 24 July 2017, Law Gazette
• "Injunction halts ‘fake news ' campaign against UK businessman", Ben Quinn, 10 July 2017, Guardian
• "Businessman 's fake news troll halted by injunction in legal first", Francis Gibb, 10 July 2017, The Times
• "Article 50 litigation—putting a spotlight on the UK 's constitution", James Libson and Katy Colton, 8 November 2016, LexisNexis Public Law Analysis
• "Gina Miller 's Brexit victory is a triumph of democracy over politics", Emily Nicholson and Katy Colton, 4 November 2016, Guardian
• "Mishcon trainee wins top law awards", 24 January 2012