Call: 1986

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For practice areas see below

"he has great presence"

he "advises comprehensively, and has a thorough understanding of the issues involved"

"he makes his case well and is a pleasure to deal with"

Chambers UK 2014

"highly sought after for advice and representation on the spectrum of tax, trusts and estates matters"

"charismatic" with a "calm and reasoned approach" and a "great sense of humour".

Clients warm to his "approachable and user-friendly manner".

Chambers UK 2012

“thoroughly good from a technical point of view” and  “never ruffled in court, knows how to push a case forward”.

Chambers UK

‘approachable and extremely helpful’

Legal 500 2010



Michael O'Sullivan has been in practice at the Bar since 1988 and his current practice incorporates:

  • trust litigation and advice both onshore and offshore
  • contentious and non-contentious probate applications
  • Inheritance Act applications (often in relation to high value estates worth several millions)
  • professional negligence (particularly in relation to claim against solicitors and accountants and tax consultants) in relation to negligent conveyancing and tax advice
  • Court of Protection applications
  • capital gains tax and inheritance tax planning
  • real property litigation (particularly in relation to easements, restrictive covenants and contracts for the sale of land)
  • pensions litigation


Professional Reputation

Michael is recommended in current editions of the Legal 500 and Chambers UK Directories for his trust and probate work and his work in the Court of Protection.


Notable Cases

Michael has been involved in a number of important and notable cases, including:

  • Re Jones [2014] EWCOP 59 – acted for the daughter in this multi-jurisdictional statutory will claim involving complex taxation issues.
  • Khan v Crossland [2012] WTLR Removal of Executor under S116 SCA 1981
  • EB v RC [2011] EWHC 3805 (CoP) Removal of Deputy under MCA 2005
  • Husain v Hussain (unreported) - approval of compromise of a claim to set aside a transaction intended to defeat a claim under the Inheritance Act.
  • Re Dawes Deceased (unreported) - application in relation to the estate of Christopher Dawes involving removal of trustee of charitable trust worth £20m.
  • Re KP - Court of Protection application re statutory will for a brain injured applicant in receipt of the largest personal injury award made against the NHS.
  • Re N - Court of Protection application involving conflicts of law and cross border jurisdictional issues.

Currently acting in

  • Re Z – Court of Protection matter where Z is a widow worth £8m.
  • Re M – Court of Protection matter involving M who is the owner of a substantial mansion house and landed estate in the Midlands and an additional landed estate in Devon
  • The Right Hon Rupert Charles Ponsonby (8th Baron de Mauley)  v Right Hon John Charles Sholto Douglas (Earl of Morton) – claim for breach of trust against executors of  tenant for life - the 6th Baron de Mauley.
  • Paul v Paul – application for Court’s blessing and order under Section 57 of the Trustee Act 1925 to enable the partition of a substantial agricultural estate in Suffolk.
  • Re P [2009] EWHC 163 (Ch) - landmark judgment  by Lewison J. on the jurisdiction of the Court of Protection to make a statutory will under the Mental Capacity Act 2005.
  • Carr v Ennals [2008] EWHC 2859 (Ch) - probate challenge to will on grounds of lack of capacity in a case where the testator was suffering from a brain tumour.
  • PEER v EMC [2007] E.C.D.R 1 [2006] EWHC 2883 - succession issues relevant to claim to UK copyright in various jazz compositions by Cuban artists (as featured in the Buena Vista Social Club).
  • Allardyce v Roebuck [2004] 3 All ER 754 - time limits on testamentary options to purchase property.
  • Asylum Seekers Management Ltd v Adelphi Hotels Ltd (CA) [2003] EWCA Civ 1892 - construction of break clause in commercial agreement relating to management of properties occupied by asylum seekers.
  • Shirley v D J Freeman [2002] 01 EG 74 (CS) - successful striking out of a negligence claim where solicitors were alleged to have failed to advise client competently in relation to rights of way over common land and highways issues.
  • Banks v Cox [2001] (CA) Estates Gazette 2001: Comm Law Journal 2001 - fraudulent misrepresentation on sale of a business and test for admission of new evidence on appeals under the Civil Procedure Rules.
  • Re Lady Price [2000] - construction of gift of chattels in will and meaning of word furniture and whether it included pictures, porcelain jade and other objets d'art in context of an estate that included chattels worth £5m.
  • Re Cama - application under CPR Part 64 for construction of will of testator and approval of compromise arrangement in relation to estate worth in excess of £20m.


Advisory and Drafting Work

Michael is currently advising in relation to a prospective probate action involving the estate of an Indian gentleman possessed of a property portfolio of £18m and is advising in relation to Inheritance Tax liability in the estate of a gentleman worth £10m.

He is also acting in connection with a reorganisation of a large landed estate in Suffolk and in connection with a charitable trust fund worth in excess of £20m established under the will of the infamous Christopher Dawes. He has also been involved in a variation of the will trust of a celebrated Oxford Publisher and an associated application to the Court of Protection. He is currently defending a claim for possession of property on the grounds of estoppel involving the estate of an American Billionairess.

In recent years Michael has acted in a number of substantial trust applications involving aristocratic settlements, one of which involved a fund valued at £150m.

He has also appeared in several substantial Court of Protection applications involving patients who are high net worth individuals. He has been instructed regularly by the Official Solicitor.

He has been involved in the negotiating and drafting of the compromise of a high value divorce which involved the variation of settlements that qualified as nuptial settlements. The settlement held shares in a private company that is prominent in the fashion industry.

He has drafted and advised in relation to personal injury settlements of large multi-million pound awards of damages.



Michael is an accredited mediator, trained through ADR Chambers


Professional Memberships

Michael is a member of:

  • STEP
  • The Chancery Bar Association
  • The Property Bar Association


Publications and Lecturing

Michael is the author of:

  • Asset Protection (published by Butterworths in 2000) - a textbook on the law relating to asset protection which deals with both the English law and the law of several foreign jurisdictions
  • A Practitioners Guide to Trustee Investment (published by Lexis Nexis/Tolley in 2004) - a guide dealing with the law of trustee investment in the light of the introduction of the Trustee Act 2000

Michael is also a contributing author to the chapters on Purpose Trusts and Protective Trusts in Tolley's Trust Drafting and Precedents.

Michael has written various articles, including:

  • Trusts and Estates Law  and Tax Journal, April 2007: 'Re Horley Town Football Club' (Gifts to unincorporated associations)
  • STEP Journal, 2006: 'Trustee Investment in Private Companies'
  • Trusts and Estates Law and Tax Journal, 2006: 'Case note on Raitu v Conway (breach of fiduciary duty and piercing of corporate veil)'
  • ACTAPs newsletter, 2005: 'Professional negligence in relation to tax planning'

Michael frequently lectures and he has recently lectured on the following topics:

  • Professional negligence in connection with estate administration
  • Asset Protection (for CLT)
  • Professional negligence in relation to Trusts and Estates (for CLT)
  • Construction of wills and trusts (for STEP (Birmingham)
  • Trustee investment (for STEP (Isle of Man Conference 2005))
  • Company law issues for probate and trust practitioners (for Bristol Law Society)
  • Trust aspects of Matrimonial proceedings for Manchester STEP
  • Insolvent settlors, insolvent estates and shams for CLT October 2009