Mark Gilmartin is a Partner at JMW Solicitors and a specialist family lawyer advising high-net-worth (HNW), high-profile and private clients on complex divorce, financial remedy, children and modern family matters.
Mark has two principal areas of expertise: high-value divorce and financial remedy, including wealth and asset protection and pre- and post-nuptial agreements; and modern family law, with a particular specialism in donor conception, surrogacy and international surrogacy. He also advises parents in complex children disputes arising from relationship breakdown.
He advises clients where significant assets, complex financial structures, international issues or sensitive family circumstances require technical expertise, strategic advice and the highest levels of discretion and confidentiality. His clients include entrepreneurs, professionals, high-net-worth individuals and high-profile and celebrity clients.
Family Breakdown (Divorce), Financial Settlements and Wealth Protection
Mark advises on complex and high-value divorce and financial remedy proceedings including cases involving substantial assets, inherited wealth, business interests, trusts, pensions and other complex financial arrangements. He has particular expertise in wealth protection, asset protection and pre- and post-nuptial agreements, advising clients on protecting pre-marital, inherited and family wealth and achieving greater certainty over their financial position in the event of relationship breakdown.
Mark also advises parents in complex children disputes, particularly cases involving high conflict and difficult questions concerning arrangements for children following relationship breakdown. In 2014, Mark undertook specialist professional training and qualification to represent children in high-conflict family proceedings. This experience gives him a distinctive perspective when advising parents: he is able to approach difficult disputes with an understanding of the importance of ensuring that the child's voice, experience and welfare remain central to decision-making.
Mark is regularly sought out for his views on pre-nuptial agreements, wealth protection and the financial consequences of marriage and divorce, and has provided expert commentary to BBC News, The Times and the Financial Times on the growing use of pre-nuptial agreements and changing attitudes towards protecting wealth.
His work frequently involves clients for whom privacy, reputation and discretion are particularly important, including high-net-worth and high-profile individuals.
Modern Families, Surrogacy and Fertility Law
Mark leads JMW's Modern Families team, advising on donor conception, known and informal donation, legal parenthood, parental orders and surrogacy.
He has a particular specialism in international and cross-border surrogacy, advising intended parents on the interaction between overseas arrangements and the law of England and Wales, including issues concerning parental orders, consent and legal parenthood.
Mark was the lead solicitor for the applicant in Re Q (Surrogacy: Legal Advice) [2026] EWHC 1538 (Fam), a recently reported High Court case concerning an international surrogacy arrangement involving Kyrgyzstan and Northern Cyprus. The case is a recent example of his specialist work in complex cross-border surrogacy.
Mark is a Lawyer Supporter of the Donor Conception Network, whose directory specifically identifies JMW's Modern Families team as being led by Mark and providing expert advice, support and guidance to families exploring different pathways to parenthood. He is currently the only affiliated solicitor in England and Wales with Men Having Babies, reflecting his specialist expertise in surrogacy and his particular focus on supporting intended parents navigating international surrogacy arrangements.
He also contributes to professional discussion on donor conception and modern family law, including his DCN Perspectives article “Donor conception and UK Law: Understanding legal parenthood, responsibilities and rights”, examining legal parenthood, parental responsibility and the rights and responsibilities arising from donor conception.
Mark is a volunteer for a number of schemes including the Royal Courts of Justice CAB scheme and operates a support service at St Mary`s Church in Monken Hadley ( Hadley Wood- Barnet). Mark sits on the Resolution Collaborative Law committee and is keen promoter of trying to settle disputes outside of the Court arena saving on both financial and emotional costs of litigation.
