Niamh specialises in professional liability matters, with particular experience in claims against lawyers, valuers, insurance brokers and financial professionals. In addition, Niamh is regularly instructed to advise on policy coverage and general commercial matters.
Niamh is a confident and experienced advocate. She recently represented the successful respondents in the Court of Appeal case of Guo v Kinder & others [2024] EWCA Civ 762, which concerned the date of issue of a claim form in professional negligence proceedings in circumstances where an earlier unsuccessful attempt to issue had been made.
She also represented the successful solicitor defendants in the recent High Court case of Playfair v Pannells LLP & Shakespeare Martineau LLP and others [2024] EWHC 1933 (Ch), where an application to extend time for service of a multimillion-pound claim was refused.
In March and May 2023, Niamh acted as sole counsel in a six-day professional negligence trial. Niamh represented a firm of solicitors defending a claim of professional negligence in connection with the conduct of a defence of an intellectual property claim and the pursuit of a commercial counterclaim. The court dismissed the professional negligence claim, finding that none of the 17 allegations of breach of duty had been made out, and that the claim would have failed, in the alternative, on causation. Costs were agreed in a sum in excess of the defendant’s costs budget.
In June 2023, Niamh acted as sole counsel in a three-day professional negligence trial. Niamh represented a firm of solicitors defending a claim in professional negligence in connection with the conduct of criminal proceedings in circumstances where the claimant’s conviction had been overturned by agreement on appeal. The court dismissed the professional negligence claim, finding that none of the 12 allegations of breach of duty had been made out, and that the claim would have failed, in the alternative, on causation. Costs were awarded on the indemnity basis with a payment on account of 99.5% of the defendant’s costs budget.
Niamh has acted in litigation against all manner of professionals, including insurance brokers, estate agents, funeral directors and auditors. She has particular experience of claims against lawyers, surveyors/valuers and financial professionals.
Lawyers
Niamh has substantial experience in the field of solicitors’ and barristers’ negligence. She accordingly has specialist knowledge on issues including limitation (with a special interest in section 14A and section 32 of the Limitation Act), causation, duty of care, quantification of damages including loss of a chance and claims for contribution from third parties. She has acted in disputes involving allegations of negligence, breach of fiduciary duty and breach of trust against lawyers in virtually every conceivable area of legal practice. She has a special interest in claims relating to negligence in the preparation of wills.
Surveyors & valuers
Niamh is frequently instructed in claims against surveyors/valuers and is currently instructed in several claims by lenders alleging overvaluation of property portfolios.
Financial professionals
Niamh is regularly instructed in claims against IFAs, and is currently involved in several cases involving allegations of unsuitable investment advice and mismanagement of investments.
Niamh is regularly instructed to advise on matters of policy coverage and contractual disputes. She has advised and represented clients in disputes relating to arbitration, conflicts of law, registration of foreign judgments and general contract law. She has advised and prepared submissions in her own right for the appeal of a multi-million dollar arbitral award. She has also acted in High Court and Court of Appeal proceedings under sections 67 and 72 of the Arbitration Act 1996 (with Vernon Flynn KC).
Niamh is very experienced in professional disciplinary proceedings, having represented over 100 nurses before the Nursing and Midwifery Council in respect of all manner of allegations. Her focus is now on the defence of solicitors before the Solicitors Disciplinary Tribunal, work which she particularly enjoys.
Guo v Kinder & others [2024] EWCA Civ 762 (successful defence of appeal to the Court of Appeal on question of date of issue of claim form)
Playfair v Pannells LLP & Shakespeare Martineau LLP and others [2024] EWHC 1933 (Ch) (successful defence of application to extend time for service of a multimillion-pound claim)
Re Sherlock Holmes International Society [2016] EWHC 1392 (Ch); [2016] 4 W.L.R. 173; [2016] P.N.L.R. 31 (successful defence of solicitors in claim for breach of warranty of authority)
Turner v Bromets Jackson Heath LLP [2016] (Leeds County Court, HHJ Behrens) (successful defence of solicitors accused of negligence in respect of a declaration of trust between co-habitees)
Harding Homes v Bircham Dyson Bell [2015] EWHC 3329 (Ch) (ten-day trial resulting in successful defence of solicitors despite admitted breach of duty (with William Flenley KC))
"Niamh O'Reilly is hugely bright and an excellent barrister. She is engaging and very strong in court and on paper, particularly with the detail. A very pleasant person to work with." Chambers UK, 2025
"Niamh has very good technical knowledge and commercial awareness." Chambers UK, 2025
"Niamh's technical and procedural knowledge is fantastic. Her advocacy at trial is extraordinary, second to none." Chambers UK, 2025
"Niamh is phenomenally bright and well able to deal with the most complex cases. She is enjoyable to work with too." Legal 500, 2025
"Niamh is a great advocate and equally at home in court or providing written advice." Chambers UK, 2024
"Niamh is excellent and very user-friendly." Chambers UK, 2024
"She is utterly brilliant and the best and most user-friendly barrister I know for professional negligence cases." Chambers UK, 2024
"Very approachable and easy to work with and good technically." Chambers UK, 2024
"She is my go-to barrister on complex professional negligence claims. She is a very impressive person and this shines through in her work." Chambers UK, 2024
"Niamh is always a delight to work with. She is very thorough in her preparation and an exceptional advocate." Legal 500, 2024
"Niamh is a delight to work with. She combines her sharp intellect with a lovely manner, putting even the most nervous clients at ease." Chambers UK, 2023
"Niamh O'Reilly receives superb reviews from her clients, denoting her as a barrister with experience and authority beyond her years.” Chambers UK, 2023
"Niamh is the first name on the list of recommendations whenever clients or colleagues need a barrister for the most complex or 'nasty' cases." Chambers UK, 2023
"Niamh has a wealth of experience and knowledge, and always impresses me." Chambers UK, 2023
"Really personable, lovely to deal with, bright, commercial and clear." Legal 500, 2023
"Niamh is a very bright and articulate barrister. She has sound commercial judgment and is an impressive advocate." Legal 500, 2023
“She’s brilliant, my go-to for higher-value solicitor negligence cases below the silk level.” Chambers UK, 2022
“She’s an exceptionally good barrister, she gets the judge on side – just incredibly good, a real rising star.” Chambers UK, 2022
“Extremely hard-working, gets into the detail, and very supportive to solicitors on the black-letter advice but also the whole perspective. She is able to give very authoritative advice in very complex areas.” Chambers UK, 2022
“Niamh combines extreme intelligence and an approachable personality. She excels in explaining the most complex legal issues to clients and the court.” Legal 500, 2022
“She has a no-nonsense approach to advocacy and is excellent on her feet. I have every confidence that she will achieve what she sets out to achieve.” Legal 500, 2021
“Great technical knowledge” Legal 500, 2020
“Gets to grips with novel subject matters very quickly” Legal 500, 2019
“She is extremely bright, gives pithy advice and is a tenacious advocate.” Legal 500, 2017
Awards
Education
ICO Data protection registration number: Z1653764.
Niamh O’Reilly is a barrister regulated by the Bar Standards Board. Click here to view Niamh O’Reilly’s Privacy Notice
