Olivia Magennis MCIArb

Practice Overview

• Children (Public Law)
  Olivia has a busy Public Law practice and acts for parents, children and their Guardians and Local Authorities. Olivia regularly represents vulnerable parents, and has particular experience with clients with learning disabilities and mental health problems.  

   

  Olivia's areas of experience include: 

  • Serious physical injury, including complex and conflicting medical evidence;
  • Sexual abuse;
  • Factitious or Induced Illness (FII)/Insulin poisoning; 
  • Serious domestic violence;
  • Disclosure and public interest immunity (PII) issues relating to children;
  • Neglect; 
  • Revocation of Placement Orders.

  Notable cases include:

   

  Williams & Anor v LB Hackney [2018] UKSC 37

   

  Re B [2018] EWCA Civ 20

   

  X County Council v AB [2015] EWFC 98

   

  PD v SD [2015] EWHC 4103 (Fam)

   

  P v Local Authority [2016] EWHC 2779 (Fam)

   

  A Local Authority v B [2017] EWCA Civ 1635
• Children (Private Law)
  Olivia is regularly instructed in complex private law proceedings, including:

  • All aspects of child arrangements order, including ‘implacable hostility’ cases, ‘no contact’ cases and shared care arrangements; 
  • Representation of the child through a r16.4 Guardian; 
  • Temporary/permanent leave to remove from the jurisdiction;
  • Internal relocation;
  • Disputes between same-sex couples regarding child arrangements; 
  • Allegations of physical, sexual and emotional abuse;
  • Education, religion and change of name disputes.
• Judicial Review & Administrative Law

  Olivia has experience of cases involving public policy in family law. She has acted pro bono in test cases involving issues of legal aid, human rights and the lawfulness of actions taken by public bodies.

• Domestic Violence & Injunctions

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

• Court of Protection

  Olivia is developing a practice in the Court of Protection. 

• Arbitration

  Olivia is an arbitrator, qualified to take on children work.

• Modern Families & Surrogacy

  Olivia also acts in cases involving donor-conceived children and children born through surrogacy arrangements. She has appeared in the High Court and Court of Appeal in such cases, including applications for parental orders, declarations of parentage and private law disputes.

• What the Directories Say

  "She is utterly committed to the client and the case, giving it her all. She is so good at managing difficult cases and is always 100% on board with the client." Band 4 - Chambers and Partners, 2025

  "Olivia is an excellent advocate, who turns around cases with the strength of her submissions." Band 4 - Chambers and Partners, 2025

  "Her cross-examination is a masterclass to behold." Band 4 - Chambers and Partners, 2025

  "An excellent advocate who prepares thoroughly." Band 4 - Chambers and Partners, 2024

  "Olivia is very considered and suitably attentive to the detail on very complex cases that demand in-depth knowledge of a lot of papers at short notice." Band 4 - Chambers and Partners, 2024

  "Olivia is a true asset on any case she is instructed on." Band 4 - Chambers and Partners, 2024

  "Olivia is an excellent advocate, clear, concise, and pragmatic. She is great in terms of thinking of strategy and the bigger picture. She is an extremely strong and persuasive advocate. She has amazing client rapport and is a go-to barrister in complex children's act matters." Legal 500, 2024

  "Olivia is fabulous at delivering unpalatable advice to clients which does not impact their working relationship. She has great approach of the court irrespective of the level of judge. Her written work is on a par with her excellent advocacy."  Legal 500, 2023

  “She leaves no stone unturned when considering the papers. Olivia is a firm advocate and has a solid grasp of the law and is one of the most empathic but realistic barristers.” Tier 5 – Legal 500, 2022

  “Is a no-nonsense, straight talking barrister, who always prepares better than the opposition and is able to fight her clients’ corner with a high degree of effectiveness. A force to be reckoned with in the courtroom. She’s a real class act!” Tier 5 - Legal 500, 2021

• Notable Cases

  H & Anor v S & Anor [2024] EWHC 730

  Re C (Surrogacy: Consent) [2023] EWCA Civ 16

  Z (Surrogacy: Step-parent Adoption), Re [2024] EWFC 20

  X v Y [2022] EWFC 77

   

  Re Ms L; Ms M (Declaration of Parentage) [2022] EWFC 38

   

  X (A Child: Surrogacy: Marriage) [2018] EWFC 15

   

  Williams & Anor v LB Hackney [2018] UKSC 37

   

  Re B [2018] EWCA Civ 20

   

  X County Council v AB [2015] EWFC 98

   

  PD v SD [2015] EWHC 4103 (Fam)

   

  P v Local Authority [2016] EWHC 2779 (Fam)

   

  A Local Authority v B [2017] EWCA Civ 1635