Aidan O'Brien

Aidan is an absolute dream to work with - he's hardworking, he goes the extra mile and is charming and persuasive with clients, witnesses and experts

Legal 500 2023

Aidan is ranked as a ‘Leading Junior’ in both the Legal 500 and Chambers UK, where he is recognised as ‘a brilliant barrister. He is very good on his feet at court and in ADR.’  He specialises in high-value personal injury, clinical negligence and commercial law.

Aidan’s work is evenly split between claimants and defendants.  He undertakes work throughout England and Wales.

Aidan specialises in catastrophic claims, including brain injuries, tetraplegia and fatal accidents.  He is adept at dealing with claims involving complex medical and causation issues.

Aidan also has significant expertise in claims giving rise to allegations of fundamental dishonesty and fraud.

In addition to his court work, Aidan has a busy paperwork practice, providing a swift turn-around for pleadings as well as advice on prospects, tactics and quantum.  Aidan regularly represents clients at RTMs and mediations.

Aidan is also a contributing editor of ‘The Law of Limitation’ (Bloomsbury Professional).

The Legal 500 - The Clients Guide to Law Firms

Clinical Negligence

Aidan enjoys an extensive medical practice, ranging from complex clinical negligence claims, regulatory discipline and medical product liability. He has a Master’s degree in Healthcare Law & Ethics and has been published in the British Medical Journal.

Aidan represents both claimants and defendants (NHS Resolution, medical defence organisations, private hospitals and independent clinicians) in the full panoply of negligence claims.

Aidan has particular expertise in claims arising from:

  • Missed cancer diagnoses.
  • Cauda equina syndrome.
  • Lack of informed consent.
  • Obstetric injuries, including shoulder dystocia.
  • Compartment syndrome.
  • DVT and pulmonary embolism.
  • Spinal injuries.
  • Hypoxic brain injuries.

Recent instructions include as sole counsel:

  • Cauda equina syndrome claim, valued at >£2.5 million.
  • Defending a claim alleging that the improper use of a vaccine led to chronic fatigue syndrome, pleaded at >£7 million.
  • Claims arising from allegations of negligent delivery due to excessive traction, causing Erb’s palsy and life-long disabilities, pleaded at >£3.7 million.
  • Claim arising from the development of chronic kidney disease following the improper use of medication, pleaded at > £5 million.
  • Various high-profile claims arising from inappropriate surgery and lack of informed consent, arising from an Orthopaedic Surgeon in private practice.
  • Claim arising from a ‘never event’ involving the removal of the wrong bone during surgery.

Aidan is also trained as a Nursing & Midwifery Council Case Presenter and has experience in a wide range of medical regulatory hearings.

Personal Injury

Aidan enjoys a busy personal injury practice with a particular focus on:

  • Catastrophic injuries
  • Spinal injuries
  • Traumatic brain injuries
  • Amputation claims
  • Fatal accidents
  • Clinical negligence claims

Aidan is frequently instructed to deal with multi-million-pound claims.  He is recognised for his grasp of difficult medical issues and causation disputes.

Aidan regularly conducts conferences with experts, attends JSM/RTMs and fights cases to trial.  He is particularly adept at cross examining expert witnesses.

Aidan has significant experience of dealing with fundamental dishonesty and fraud claims.

Acting for both claimants and defendants, Aidan has gained useful insight into the approach taken by each side.

Civil Fraud

Aidan has considerable experience dealing with fraud and fundamental dishonesty. He frequently is instructed to defend high value RTA and insurance claims on the basis of exaggeration, misrepresentation and dishonesty.

Aidan has successfully obtained a series of contempt of court findings in the High Court, arising from breaches of court orders and perjury.  Aidan has managed to secure a raft of fundamental dishonesty findings, following the discontinuance of personal injury claims.

Aidan frequently provides industry training to large insurance groups in regards to LVI, phantom passenger, staged accident claims and fraud rings. He also provides seminars and workshops dealing with the best use of social media and convert surveillance evidence.

Aidan also has significant expertise in relation to defending credit hire claims, on the basis of fraudulent misrepresentation.  Aidan has had a large number of high value claims dismissed on the basis of enforceability of hire agreements, following false statements made by CHOs about the claimant’s liability to pay credit hire charges which induced them into the CHA.

Aidan also successfully defended the appeal of Putta v Royal & Sun Alliance [2020] EWHC 117 (QB), wherein a claimant’s evidence was found to be self-serving and untruthful.


Aidan regularly acts on behalf of individuals, large businesses and insurance companies in a wide range of high value commercial and contractual disputes. He is frequently instructed to advise on complex issues of law and is lauded for his clear-sighted grasp of practical and commercial considerations.

Aidan regularly advises on complex issues of insurance law and provides readily comprehensible guidance to his clients. He is noted for his effective courtroom advocacy, especially when dealing with intricate legal issues.

Aidan has a particular interest in dealing with fraudulent claims and has experience of complicated multi-track disputes.

Regulatory & Disciplinary

Aidan specialises in academic appeals relating to secondary, tertiary and vocational studies. He regularly represents students at disciplinary hearings, arising from accusations of misconduct, ranging from plagiarism, collusion and sexual misconduct.  Aidan was recently interviewed for a Radio 4 documentary relating to university misconduct hearings.

Aidan also has experience in professional disciplinary hearings, across a wide range of sectors. Aidan’s extensive medical practice allows him to provide informed advice and robust representation at medical disciplinary tribunals. He also provides written advice on all aspects of disciplinary and regulatory law.

Sports Law

Aidan is a member of Chambers’ Sports Disciplinary and Regulatory group. He has extensive experience as an adjudicator, in his capacity as a Judicial Officer for World Rugby, European Professional Cup Rugby (‘ECPR’) and the Rugby Football Union (‘RFU’).  Aidan chairs disciplinary panels arising from international test matches, European Cup, Premiership, Championship and National Leagues 1 & 2 fixtures.

In September 2021, Aidan was appointed by the Football Association (‘FA’) to sit as a Judicial Panel Member.  His role involves hearing cases or appeals in connection with disciplinary and other regulatory processes of The FA, such as anti-doping and integrity.

Aidan also has experience of representing athletes in a range of sporting contexts.  He deals with claims arising from contractual, competition and personal injury disputes.

Travel & International Law

Aidan has a busy personal injury and clinical negligence practice, with a cross-jurisdictional dimension.  He regularly acts for both claimants and defendants, providing specialist advice and advocacy.

Aidan accepts instructions in respect of a wide range of international injury claims, in respect of road traffic accidents, food poisoning, medical negligence or cosmetic treatments. Aidan also deals with claims under the Package Travel Regulations 1992 and the Package Travel and Linked Travel Arrangements Regulations 2018.  He also has a wealth of experience of claims involving allegations of fraud and fundamental dishonesty.

Aidan regularly provides bespoke training and seminars for clients, which can be arranged upon request.

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Notable Cases

Jarman v Brighton & Sussex University Hospitals NHS Trust [2021] EWHC 323 (QB)
Aidan successfully defended a £2.4 million Cauda Equina Syndrome (‘CES’) claim, in circumstances where the Claimant was permitted to rely upon her own experts, as well as a suite of experts instructed by a second defendant in separate, but related, proceedings, who discontinued prior to trial.

X v Y NHS Trust [2021]
Aidan obtained a >£600,000 settlement on behalf of a family after the suicide of the husband/father. The deceased’s death would have been prevented if the defendant trust’s mental health team had appropriately assessed him in the days prior to his death.

KS v BH Healthcare [2020]
Aidan secured a £90,000 settlement on behalf of an elderly patient who suffered pressure sores as a consequence of the defendant’s negligence.

Read more

Putta v Royal Sun Alliance [2020] EWHC 117 (QB)
Aidan successfully resisted an appeal against HHJ Venn’s finding that a Claimant was sufficiently pecunious to self-fund vehicle repairs and an alternative vehicle, pending those repairs, in circumstances where the Claimant would be required to use his credit cards and overdraft.

Kadir v Thompson (2016, Central London County Court, HHJ Luba QC)
Aidan successfully defended a credit hire claim on the basis of fraudulent misrepresentation at first instance and on appeal.

Read less

If you would like to instruct Aidan O’Brien or would like help or advice in doing so, please call and talk to our excellent clerking team, led by Chief Executive/Director of Clerking, Paul Cray. Our phone number is +44 (0)20 7583 9241. Alternatively, please email us at

For more information about our clerking team, please click here for the clerks page.

Appointments & Memberships

    • Football Association, Judicial Panel Member
    • World Rugby, Judicial Officer
    • European Professional Cup Rugby (‘ECPR’), Judicial Officer
    • Rugby Football Union Judicial Panel
    • British Association for Sport & Law.
    • Personal Injuries Bar Association.
    • London Common Law & Commercial Bar Association.
    • Association of Regulatory & Disciplinary Lawyers.
    • Association of Contentious Trust and Probate Specialists ‘ACTAPS’

Education & Qualifications

  • BPTC, City Law School, London.
  • MA Healthcare Law & Ethics, University of Manchester.
  • BA Law & Politics, University of Manchester.
  • St Colman’s College Grammar School, Newry, Northern Ireland.


I have had the pleasure of working with Aidan for the last four/five years. Aidan is an excellent barrister and in my view, stands out from other barristers because of his attention to detail and his quick thinking when faced with a difficult situation. Aidan also goes the extra mile with the witnesses, to make them feel at ease and keeping me happy at the same time.

Recently, we attended a Trial together. I normally pride myself in my attention to detail but Aidan spotted something that I had not and, as a result, got us out of what could have been a very sticky situation. Following the Trial, although we settled, the witness told me how impressed he was with Aidan; in particular the calm manner in which he dealt with the situation and the way Aidan made him feel at ease.

Aidan is also very helpful when it comes to “non fee” work and has carried out a number of seminars for my firm and is always happy to help. Recently I managed to persuade him to undertake the Three Peaks Challenge with me! I am not sure Aidan has forgiven me for that yet! I look forward to working with Aidan in the future.

Narrinder Taggar


Shakespeare Martineau


At DWF, my causation team and I have worked with Aidan over the past few years  and he has provided exceptional success with his advocacy. We believe that he is thorough, evidences strong technical ability, is enthusiastic and is well liked by our clients.

Jewels Chamberlain

Director, Fraud & Insurance Team



Thorough, knowledgeable, very responsive and personable…

Avinder Sidhu

Senior Associate, Clinical Negligence Department



Approachable and very client friendly. Knowledgeable in the area of contentious probate in which I would not hesitate to instruct Aidan again.

Tracey Leathley

Specialist Probate Solicitor

Lyons Davidson



Directory Quotes

‘Aidan is a brilliant barrister. He is very good on his feet at court and in ADR.’

Legal 500 2024 – Ranked Leading Junior in Clinical Negligence – Tier 3

‘Aidan is an absolute dream to work with – he’s hardworking, he goes the extra mile and is charming and persuasive with clients, witnesses and experts’

Legal 500 2023 – Ranked Leading Junior in Clinical Negligence – Tier 3

‘Aidan always provides very sensible advice. An excellent barrister who understands the client’s needs.’ 

Legal 500 2022 – Ranked Leading Junior in Clinical Negligence – Tier 4



  • The British Medical Journal: ‘Lessons from the Ashya King case’.
  • The Guardian: ‘Nothing but the Truth’.
  • Farrar’s Building Website: ‘Consent to Medical Treatment – Montgomery v Lanarkshire Health Board’
  • Farrar’s Building PI Update: ‘Accidents Abroad: Jurisdiction, Liability and Damages’
  • Employment Law Update 2014: ‘Third Party Harassment after the Repeal of S.40 EqA’.
  • Farrar’s Building EL Seminar ‘S. 69 of the Enterprise and Regulatory Reform Act 2013’