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Portrait of Karen Denny

Karen Denny


CMS Cameron McKenna Nabarro Olswang LLP
Cannon Place
78 Cannon Street
United Kingdom
Languages English

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.

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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

"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.
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Lectures list

  • Presentation / seminar at the UK Supreme Court in December 2015
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  • 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
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High Court rules there is no im­munity to per­son­al in­jury claim arising...
Sum­mary The High Court has con­sidered the ap­plic­a­tion of the ex­cep­tion to state im­munity, con­tained in sec­tion 5 of the State Im­munity Act 1978 (“SIA”), in a per­son­al in­jury claim  com­menced by Mr...
No dip­lo­mat­ic im­munity for per­pet­rat­ors of mod­ern slavery
In a ground­break­ing judg­ment, the UK Su­preme Court has ruled, for the first time, that the al­leged ex­ploit­a­tion of a do­mest­ic work­er falls with­in the com­mer­cial activ­ity ex­cep­tion to a dip­lo­mat’s im­munity...
High Court con­siders the ap­plic­a­tion of the ser­vice pro­ced­ures in sec­tion...
Sum­mary In a judg­ment handed down on 14 March 2022, the High Court has de­cided that the de­fend­ant na­tion­al flag car­ri­er of Sur­i­n­ame (re­ferred to as “SLM”) was not en­titled to be served with a Claim...
CMS In­ter­na­tion­al Dis­putes Di­gest - 2021 Sum­mer Edi­tion
Wel­come to the 2021 sum­mer edi­tion of our In­ter­na­tion­al Dis­putes Di­gest, a bi-an­nu­al pub­lic­a­tion fea­tur­ing ana­lys­is and com­ment­ary on the key trends cur­rently shap­ing the glob­al dis­pute res­ol­u­tion mar­ket.As...