Diarmuid’s practice is focussed on commercial litigation and arbitration. He has particular interests in insurance / reinsurance, professional liability, civil fraud, construction and sports law. He is ranked by the Legal 500 as a ‘Rising Star’ in insurance and professional liability, and as a Leading Junior in sports law.

His current and recent instructions as junior counsel include substantial proceedings before the Supreme Court, the Commercial Court and the European Court of Human Rights. Diarmuid relishes his role as an advocate and appears regularly as sole counsel in trials and applications before the High Court and County Courts, in domestic and international arbitrations in insurance and sports matters, and in heavy construction adjudications.

Diarmuid has been described in the legal directories as “an excellent advocate and thinks quickly on his feet. Excellent drafting skills, very thorough and always gets into the detail of the matter.” He prides himself on being responsive and a team player, and always seeks to give practical, commercially-focussed advice.

Further details of Diarmuid’s recent and ongoing work are provided in the tabs on individual practice areas below.

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Areas of Expertise



Recent instructions include:

• Acting in a High Court misrepresentation / fraud claim.

• Acting for a retail bank in its defence of a claim relating to the sharing of information with credit reference agencies.

• Assisting Can Yeginsu in advising on a dispute regarding the termination of an international software reselling agreement.

• Assisting Tom Ogden in advising on a partnership dispute arising from a broadband venture.

• Acting for an estate agency claiming fees due under a joint sole agency contract.

• Advising on the regulatory compliance of a claims management company’s commercial arrangements.



Recent instructions include:

• Acting as sole counsel on behalf of the defendant in the TCC case of Jeffrey Salmon v Metropolitan Development Consultancy Ltd HT-2019-000278 arising out of the refurbishment of a high-value property in London.

• Acting as junior counsel on behalf of the second defendant in the TCC case of Evolve Housing & Support v Bouygues (UK) Limited & Ors HT-2021 000005, a multimillion pound claim arising out of the allegedly negligent design and installation of cladding at a large development in South London.

• Acting as sole counsel on behalf of the Respondent in a complex, multi-million pound adjudication arising out of a large scale infrastructure project.

• Successfully representing a contract administrator in defending an adjudication in which it was alleged to have negligently over-certified payments due under a construction contract.

• Successfully representing claimants at the multi-track trial of their claim in respect of the failure of iron window frames, installed as part of a high-value refurbishment of their beach-side home.

Insurance / Reinsurance


‘Always delivers reliable commercial advice.’ – Legal 500, 2021

Recent examples of Diarmuid’s work in this area include:

• Advising a multinational insurance company in the various proceedings worth over £10 million precipitated by a suspected, large-scale fraud.

• Acting as sole counsel in advising a wind turbine operations and maintenance contractor and its liability insurer on liability and coverage issues arising from a major wind turbine fire which led to approximately £2 million worth of damage.

• Representing the Defendant reinsurer as sole counsel in an ad hoc international arbitration worth several hundred thousand pounds.

• Advising an international insurance group on the scope of the duties, if any, owed by solicitors firms to the after-the-event insurers with whom they place their client’s ATE risks.

• Successfully represented, as junior counsel, the defendant reinsurer in a £5 million Dubai DIFC-seated UNCITRAL arbitration, through which the claimant sought an indemnity under the parties’ facultative reinsurance treaty.

• Advising and representing a national insurer in a series of cases in which the insurer sought to decline the claims of policy-holders on the basis of the fraudulent claims exception contained in the insurer’s standard policy wording.

Professional Liability


‘He is an excellent advocate and thinks quickly on his feet. Excellent drafting skills, very thorough and always gets into the detail of the matter’ – Legal 500, 2021

Recent examples of Diarmuid’s work in this area include:

Spire Property Development LLP & Anor v Withers LLP CL-2018-000578 in which Diarmuid acted as junior counsel on behalf of Withers in defending Commercial Court claims for £12 million brought by two property development companies.

Prime London Residential Development Jersey Master Holding Ltd v Withers LLP CL-2018-000811 in which Diarmuid acted as junior counsel for the defendant firm in defending a Commercial Court claim brought by a property developer for £16 million.

OOCL v Ince & Co CL-2020-000634 in which Diarmuid is currently representing the claimant shipping conglomerate as junior counsel in a £5m claim against a City law firm in respect of its alleged mishandling of an international arbitration.

• Successfully representing a firm of criminal defence solicitors in striking out a £600,000 counterclaim, through which the defendants alleged that the firm mishandled their high-profile proceeds of crime confiscation proceedings.

Public Law and Human Rights


Recent instructions include:

• Instructed as a member of the claimant’s counsel team in the landmark case of R v Jogee [2016] UKSC 8, in which the Supreme Court substantially revised the law of secondary criminal liability, abolishing the controversial doctrine of parasitic accessorial liability.

• Instructed by Article 19 in its intervention before the European Court of Human Rights in the pending case of Ganbarova and Others v Azerbaijan, the first ECHR case to consider travel bans as restrictions of the right to freedom of expression.



His approach is incredibly professional and very strategic, distilling matters for lay clients.” – Legal 500, 2021

Diarmuid is ranked as a Leading Junior in Sports Law by the Legal 500.

Recent examples of Diarmuid’s work in this area include:

• Acting on behalf of the defendant in the pending case of Frederik Tylicki v Graham Gibbons QB-2019-000545. The claimant seeks £6 million in damages in respect of catastrophic injuries he sustained during a riding accident, alleging that the accident was caused by dangerous riding on the part of the defendant. The case raises important questions about the scope of the duty of care owed by one participant in a dangerous sport to another, and the relationship between that duty to the rules of the game.

• Acting on behalf of the Royal Society for the Prevention of Cruelty to Animals in the case of Susan Mears v RSPCA QB-2020-00222, in defending a claim for the lost value of a competition horse that was euthanised in the RSPCA’s custody under the Animal Welfare Act. The Claimant is also suing for the return (or alternatively the value) of two other competition horses seized from the Claimant’s farm.

• Instructed by a national betting company in a dispute as to whether a number of large bets, worth hundreds of thousands of pounds, are payable under the company’s standard contractual terms.

• Advising the owner of a stud farm on claims in negligence against Northern Irish and English veterinary surgeons who produced pre-purchase veterinary reports on a competition horse subsequently bought by the client.

• Successfully defending a national governing body in a challenge to its refusal to admit an athlete to its high performance programme.

• Successfully defending a professional athlete against charges of possession and attempted use of a prohibited substance at a multi-day hearing before the National Anti-Doping Panel.

• Successfully prosecuting an underage athlete on behalf of a national governing body for use of a prohibited substance, leading to a 4-year ban under the WADA Code.

• Acting for the Appellant before the National Anti-Doping Panel in Hosseinpoor v UKAD (SR/NADP/667/2016), in which the Appellant was granted a 50% reduction in his two year additional sanction for training in breach of an existing anti-doping ban.

Qualifications & Memberships

Batchelor of Civil Law, University College Dublin (First Class Honours); BCL, Oxford University (Distinction).

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