Partner

Karen Denny

Languages

English

Social media

Karen covers all areas of corporate disputes, particularly those with an international law and cross border emphasis. Her experience includes advising on matters of sovereign immunity, freezing injunctions, the enforcement of foreign judgments, and obtaining evidence for use in overseas proceedings, complex fraud and contractual disputes, defamation, confidentiality and privacy disputes.

Karen has represented various sovereign states and their governmental agencies, international organisations and other entities in relation to public international law matters in particular regarding their unique immunities and privileges. She leads the public international law practice group and has been ranked as a Leading Individual by Legal 500 in Public International Law since 2018.

Awards & Recognitions

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"It is rare for a law firm to understand so well the issues that are specific to multilateral development banks, which straddle both the private sector and public sector worlds. In this regard, Karen Denny, and the CMS team by association, stand out."

Legal 500, 2025
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"Clients highlight Karen Denny for her deep understanding of matters related to public international law."

Legal 500, 2025
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"an outstanding lawyer."

Legal 500, 2023
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"Karen Denny is outstanding. She has a breadth of knowledge in this area which is impressive. She is also excellent with clients."

Legal 500, 2021
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"Karen Denny is a class act. She always puts the client first, and has a deep interest in and knowledge of the public international law field."

Legal 500, 2021

Relevant experience

United States of America – acting on its behalf in its successful assertion of state immunity in the House of Lords, Holland v Lampen-Wolfe [2000] 1 WLR1573.
US Secretary of State for Health – acting on his behalf in obtaining one of the first orders of its kind for disclosure by a third party under CPR5.4C(2) for the provision of various medical reports from the UK MMR litigation for use in the US MMR autism group litigation, Sayers & Ors v Smithkline Beecham Plc & Ors [2007] EWHC 1346(QB).
Costco Wholesale – acting on its behalf in respect of the construction of certain NHS Ophthalmic Regulations in the matter of Costco Wholesale UK Ltd v Milton Keynes Primary Care Trust [2008] ALL ER (D) 265.
SEC – acting on its behalf in its successful application for the continuance of a freezing injunction unanimously upheld by the Court of Appeal, in what is believed to be the first decision of its kind in granting the order to a foreign claimant without the requirement for a cross undertaking, United States Securities and Exchange Commission v Manterfield [2008] ALL ER (D) 218.
SEC – acting on its behalf in the successful grant of a freezing injunction in relation to Sir Allen Stanford, and various Stanford companies’ assets in the UK United States Securities and Exchange Commission v Stanford International Bank Limited and Others [2009].
Acting on behalf of the Liquidators of KSF (IOM) Limited in Kaupthing Singer and Friedlander Ltd [2009] EWHC 740 (Ch).
Acting on behalf of the Liquidators of KSF (IOM) Limited in Brazzill & Ors v Willoughby & Ors Court of Appeal [2010] EWCA Civ 561
United States of America – acting on its behalf in relation to whether it is bound to consult with its local civilian employees about redundancies before taking the decision to close a military base as a result of strategic policy re-alignment decisions, and how domestic statutes should be interpreted to give effect to customary international law, United States of America v Nolan [2015] Supreme Court.

Lectures list

Presentation / seminar at the UK Supreme Court in December 2015

Education

1986 – Law LLB (Hons) –First Class – Leicester University
1987 – Law Society Finals – First Class – Chester Law School
1987 – City of London Solicitors Company Alfred Syrett Award

Practice Areas

Dispute Resolution Commercial Disputes Corporate Crime, Compliance and Forensics

Insights

Global Reach

UK Pay Gap Report 2024