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Siobhan Lomasney

+44(0)20 7870 3876

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Partner - Family Law

Siobhan has specialised in matrimonial work, family work and civil litigation for more than 37 years. Her broad family practice includes divorce and the dissolution of civil partnerships, complex matrimonial and family financial claims, jurisdiction and cross border disputes, co-habitee disputes, disputed wills and claims against estates.

Siobhan acts for high net worth individuals, often with a public profile and is increasingly involved in complex matrimonial disputes involving children and/or with an international element.

Siobhan's experience of civil fraud recovery enables her to bring a commercial approach and forensic eye to complex matrimonial finance cases involving worldwide assets, trusts and cases of non or incomplete financial disclosure. She will pursue spouses who refuse to provide full financial disclosure and who do not co-operate with the court process and has made successful applications against spouses in contempt of court for non-disclosure of financial assets, some resulting in prison sentences.

Siobhan also has significant experience acting for the victims of harassment and stalking.



  • Divorce proceedings and civil partnership dissolution
  • Matrimonial financial disputes and claims, including Arbitration and ADR
  • Family and relationships
  • Financial Settlements
  • Disputes relating to contact with and care of children, including applications to remove from the jurisdiction
  • Fraud recovery
  • Harassment protection
  • Pre-nuptial and post-nuptial agreements
  • Professional negligence
  • Co-habitee disputes

Career Highlights

  • Acting for high-profile individuals in respect of harassment by a US citizen across multiple jurisdictions.
  • Acting for the wife in financial remedy proceedings where the husband was evasive and uncooperative in respect of disclosure of assets situated in the UK, off-shore and Europe and subsequent complex enforcement issues, including enforcement of orders in Europe.
  • Representing a UK citizen following the breakdown of his civil partnership to an Australian national which included acting to prevent the disposal of the former matrimonial home in Australia registered in the name of the opposing spouse. A request to establish the parties interest in the property was referred to the Supreme Court in Australia.
  • Acting for the wife in divorce proceedings involving valuable and complex shareholdings. The Wife received the full value of her shareholding and a substantial share of non-company assets.
  • Advising a US citizen in a substantial fraud recovery matter and in a related claim against a UK private bank that had released funds to a fraudster and achieving a substantial settlement
  • Acting in a case for a husband against a high net worth spouse involving a difficult jurisdiction dispute and involving investigation of multiple worldwide assets and successfully establishing jurisdiction of England and Wales at Court of Appeal level.

Membership & RECOGNITION

  • Resolution member
  • Legal 500




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