Practice Overview

Marlene is recognised as a leader in her field. She is consistently listed in Chambers and Partners and the Legal 500 and early in her practice was awarded the Young Barrister of the Year Award at the Jordan’s Family Law Awards 2014. She is 'regarded as a rising star by sources' and appears in law-making cases.

Marlene has a unique dual specialism in children law and in large-scale public and private inquiries. She has particular skill and experience in cases requiring the careful management of serious or sensitive allegations of harm against children. Marlene acts in all levels of court and has appeared in both the High Court and Court of Appeal with and without a leader.

  • Children (Private Law)

    Marlene frequently acts for parents and children in section 8 Children Act 1989 applications, including those which feature serious allegations, non-compliance and enforcement, require a rule 16.4 guardian, involving permission to remove children from England and Wales, and where special guardianship orders are sought. Marlene has significant experience in international cases where child abduction, jurisdiction, and surrogacy arise (including in the application of the Human Fertilisation and Embryology Act 2008).

    Marlene also regularly acts for parents and children involved in Hague Convention applications, representing applicants and defenders in the High Court. She also acts and advises in cases involving international movement of children for reasons to do with change of residence and surrogacy.

    Notable cases in private children law and international family law in which Marlene has acted include:

    Z (A Child) (Surrogacy) [2022] EWFC 18

    Al M (Children) [2020] EWCA Civ 283 

    Re K (Forced Marriage: Passport Order) [2020] EWCA Civ 190 

    AK, Re Human Fertilisation and Embryology Act 2008 [2017] EWHC 1154

    Re S (A Child) [2017] EWCA Civ 44

    K & H (Children) [2015] EWCA Civ 543

    J (A Child) (Finland) (Habitual Residence) [2017] EWCA Civ 80

    K & H (Children) [2015] EWCA Civ 543

    A v B [2015] EWHC 1562

  • Children (Public Law)

    Marlene has a busy practice in Children Act 1989 Part IV and V applications. She is experienced in matters that are complicated by chronic and serious allegations of abuse, neglect, fictitious or induced injury, and child sexual abuse and exploitation. She regularly represents parties involved in adoption applications and challenges. Marlene accepts instructions from local authorities, parents and children. She acts in complex multi-day trials where extensive findings were sought, including of induced illness and child sexual abuse.

    Notable cases in public children law in which Marlene has acted include:

    Re X (A Child) (No 4) [2018] EWHC 1815 (Fam)

    Re X (A Child) (No 3) [2016] EWHC 2755 (Fam)

    L and B (Children: Care Proceedings) [2015] EWFC 66

    In the Matter of D (A Child) (No 2) [2015] EWFC 2

    In the Matter of D (A Child) [2014] EWFC 39

  • Public Law and Inquiries

    Marlene is in demand as a junior in large-scale public and private inquiries. She is presently instructed as Junior Counsel to the Covid-19 Inquiry, focussing on the impact of the pandemic on children and young people across the UK. She is also currently acting as Junior Counsel for a Core Participant in the Post Office Horizons IT Inquiry.

    Marlene has previously acted as Junior Counsel to the Independent Inquiry into Child Sexual Abuse and to the Infected Blood Inquiry.

    Marlene has also accepted instructions in respect of external inquiries commissioned by private organisations, such as the Review of Non-Recent Child Sexual Abuse at Chelsea Football Club led by Charles Geekie KC.

    Additionally, Marlene’s practice has a focus on questions of public policy in family law. She has acted in test cases involving issues of legal aid, human rights and the lawfulness of actions taken by public bodies.

  • Domestic Abuse & Injunctions

    Marlene often represents clients who are seeking or responding to applications for injunctions linked to domestic violence or occupation of the family home.

  • Notable Cases
  • What the directories say

    "Marlene is highly eloquent and persuasive. She deals sensitively and adeptly with complex children cases." Band 3 - Chambers and Partners, 2026

    "She is very responsive and excellent at drafting complicated orders quickly. Her forensic and analytical skills are also very impressive." Band 3 - Chambers and Partners, 2026

    "Marlene has the brilliance of mastering the detail, and she is brilliant at working out what is important. I have always enjoyed working with her." Band 4 - Chambers and Partners, 2026 (Inquests and Inquiries)

    "Marlene is cool and calm, but immensely powerful in cross-examination. She knows exactly when to time her key questions for witnesses to give them maximum impact. She has a phenomenal intellect." Leading Junior - Legal 500, 2026

    "Marlene is a go-to junior barrister." Leading Junior - Legal 500, 2026 (Inquests & Inquiries)

    "Thoughtful, strategic in her thinking and a strong advocate, she's really impressive. She punches above her weight." Band 3 - Chambers and Partners, 2025

    "Experienced in international cases, always extremely well prepared and very empathetic with the clients." Band 3 - Chambers and Partners, 2025

    "Marlene cuts through the key issues and she is a really valued member of any team." Band 4 - Chambers and Partners, 2025

    "Her ability to master vast volumes of complex material and then advise at pace is truly impressive. She has a wonderful manner with clients." Band 4 - Chambers and Partners, 2025

    "She is measured, calm and unflappable. She is a real pleasure to work with." Band 4 - Chambers and Partners, 2025

    "Marlene is technically brilliant. She knows the law inside out, whatever the situation and complexity. Her advocacy is calm, measured and persuasive." Tier 6 - Legal 500, 2025

    "Very poised, excellent air of confidence, clear and compelling advocate." Tier 5 - Legal 500, 2025

    "She's able to explain difficult legal concepts in a way that's very easy to understand and more palatable than one might have first thought. Her presentation in court is lovely to see." Band 3 - Chambers and Partners, 2024

    "Marlene Cayoun is able to get to the crux of complex issues and make sophisticated arguments to the court. She's also good at breaking down difficult concepts into easily understandable language for the clients." Band 3 - Chambers and Partners, 2024

    "She has a persuasive advocacy style and has the ear of the court." Band 3 - Chambers and Partners, 2024

    "Marlene is extremely well organized when it comes to voluminous evidential material. She can understand and distil central points from complex medical evidence. She is an able advocate to whom judges listen." Legal 500, 2024

    "Marlene is really calm and puts her clients at ease. In court she's extremely clear in her advocacy style and has always got good results. She's hugely empathetic in difficult situations." Band 3 - Chambers and Partners, 2023

    "She's exceptionally knowledgeable on technical jurisdiction issues." Band 3 - Chambers and Partners, 2023

    "She is able to explain complex legal concepts in language the clients will understand, and she is receptive to their questions. She is a really fantastic lawyer." Band 3 - Chambers and Partners, 2023

     "An extremely competent and diligent barrister. She has an ability to get through a huge amount of detail and distil it down to the key issues – a skill that shows her good judgement.'"Tier 5 - Legal 500, 2023

Chambers and Partners

Ranked

Band 3 - 2026

Legal 500

Leading Junior

2026

Chambers and Partners

Ranked

Band 3 - 2025

Legal 500

Leading Junior

Tier 6 - 2025

Chambers and Partners

Ranked

Band 3 - 2024

Legal 500

Leading Junior

2024

Chambers and Partners

Ranked

Band 3 - 2023

Legal 500

Leading Junior

Tier 5, 2023

Chambers and Partners

Ranked

Band 4 - 2022

Chambers and Partners

Up and Coming

2021

Chambers and Partners

Up and Coming

2020