Katherine Illsley

Katherine Illsley
Katherine Illsley

Joint Deputy Head of Chambers
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Katherine joined 4KBW in 2011 after completion of her pupillage, specialising in family law.  Her practice covers the following areas:

  • Family Law
  • Property Law (Trusts of Land and Cohabitation Disputes)

Katherine can accept instructions in appropriate cases from members of the public under the Bar Direct Public Access Scheme.


Matrimonial Finance

Katherine’s practice focuses particularly on cases involving matrimonial finance. She has advised and acted in cases involving hidden assets, bankruptcy and also where there are parallel Proceeds of Crime Act proceedings, multiple parties and claims about trusts.

She is happy to draft prenuptial and postnuptial agreements as well as handle cases in which a nuptial agreement is in issue.

Private Law

Katherine regularly acts in private law children cases. These have included cases involving an implacably hostile parent, false allegations, issues around domestic violence and substance misuse as well as cases that have developed into care proceedings. Recent cases have included issues concerning judicial questioning, historic sexual abuse allegations and religious upbringing.

Property – Trusts of Land and Cohabitation Disputes

Katherine accepts instructions in Schedule 1 applications and TOLATA claims. Recent cases have included a TOLATA claim involving an extensive investment portfolio of properties and a claim involving an argument around proprietary estoppel. She acts in cases of cohabitee relationship breakdown as well as family investment vehicle cases where disputes over beneficial shares arise. 


Immigration: the way forward?” the second of a two-part consideration of children and immigration law, looking at how other jurisdictions tackle this issue. Published in the Legalease Family Law Journal, July 2016. It was co-authored with Agata Patyna.

No Place like Home“, the first of a two-part consideration of the rights of unaccompanied children seeing asylum within the immigration and family law process. Published in the Legalease Family Law Journal, June 2015. It was co-authored with Agata Patyna.

Protective measures” discussed recommendations to increase protection from stalking and was published in the Legalease Family Law Journal, February 2014. It was co-authored with Chris Bryden.

Several articles for Lexology and for chambers newsletters on family law topics.

Katherine frequently provides written advice on family and property law questions for the LexisNexis website.


2023: Recorder (South Eastern Circuit) (Family)

2020: Deputy District Judge (South Eastern Circuit) (Family)

“Katherine John [maiden name] is an extremely competent advocate, and is always thoroughly prepared, even at the shortest of notice. Many times, she has gone above and beyond the call of duty in assisting me and my clients. (Blackfords LLP)”

Blackfords LLP

Call: 2010
University of Oxford, BA (Hons) (English Language and Literature)
Oxford Brookes University (Graduate Diploma in Law)
College of Law, Bloomsbury (Bar Vocational Course)
Quatercentenary Scholarship (Middle Temple) 2008
Professional memberships:
Family Law Bar Association
Middle Temple

BSB Registration: