Mark is a partner in Mishcon Private, specialising in complex inter-family domestic and international trust and succession disputes often involving asset-tracing and recovery in offshore jurisdictions.
He has significant experience in advising private individuals and trustees on cross-border inheritance disputes, Will disputes, Inheritance Act claims, estate administration issues, breach of trust and proprietary estoppel claims.
Mark is a recognised leader in his field. Chambers 2014 describes Mark Keenan as a "robust litigator" who dominates the contentious trusts and estate market, both in the UK and overseas. He receives praise for his technical expertise and client care skills: "I have total faith in him. He is caring and clever, which is a great combination."
Legal 500 rankings highlighted Mark as "an individual star: hugely interventionist in a good way, and an amazing tactician" with "an encyclopaedic knowledge of the relevant cases".
Mark is a member of the Association of Contentious Trust and Probate Specialists (ACTAPS), the Society of Trust and Estate Practitioners (STEP) and the International Fraud Group (IFG). The IFG is a global network of specialist fraud lawyers across 14 countries focused on securing injunctions, asset recovery and trust busting remedies in key offshore jurisdictions.
- Acting for various members of the Dellal family in a significant, high profile family dispute brought under the Inheritance (Provision for Family and Dependants) Act 1975 (Dellal v Dellal and Others  EWHC 907 (Fam)).
- Mark represented Helena Gorbunova following the breakdown of her relationship with Boris Berezovsky and his subsequent death, which included multi-faceted claims in the Family and Chancery division, including securing multi-jurisdictional injunctions against him. Following Mr Berezovsky's unexpected death, this involved advising on multiple claims relating to his estate and ancillary litigation (Gorbunova v Berezovsky  EWHC 771 (Ch)).
- Mark acted for siblings in a long running inheritance dispute to determine whether assets held in a Liechtenstein foundation and other assets form part of their late father's estate, in a claim which involved Sharia law and the laws of Switzerland, Liechtenstein and Monaco.
- Mark acted for Mrs Zoe Stow in a complex international trust and succession dispute (Stow -v-Stow  EWHC 495 (Ch)).
- Mark represented Dr Christine Gill in the Court of Appeal who upheld the decision to overturn a will leaving the RSPCA a £2.35m farmhouse and land.
- In October 2009 the High Court in Leeds had ruled that the will leaving the family’s farm to the RSPCA was invalid (Gill v RSPCA  EWHC 2990 (Ch)). Dr Gill also succeeded in her alternative claim to the farm under the doctrine of proprietary estoppel.
- Mark represented Dr Alison Martin in her successful claim against TWM solicitors in which it was held that her late husband’s Will had not been drafted in accordance with his instructions (Martin v Triggs Turner Barton and Ors  EWHC 1920 (Ch) and also see Martin v Triggs Turner Barton and Ors  EWHC 89 (Ch)). Dr Martin also succeeded in her claims that the solicitors had given negligent advice to her concerning the tax treatment of national savings certificates held by her late husband’s estate and her entitlement to a widow's pension.
- Mark acted for a major charity in its successful defence of a legacy dispute involving a substantial Estate.
- Mark was appointed by the court to administer a multi-million pound disputed estate, which recently settled. The case involved allegations of forgery lack of due execution and want of knowledge and approval and settled at a multi-party mediation.
- Mark has been appointed to act as a Professional Deputy of the Court of Protection for a young woman who is incapable of managing her financial affairs. Mark had represented the young woman in her negligence action against her local Health Authority which settled out of court.
- Mark acted for the successful Defendants, in their challenge to the validity of their late grandmother's Will. The court found that Mrs Franks, who had testamentary capacity, did not know and understand the contents of the Will which had been prepared for her by her son who was a solicitor (Franks v Sinclair  EWHC 3365 (Ch)).
Partner, Mishcon de Reya LLP
Qualified, Mishcon de Reya
Westminster University: LLB (Hons)