John McElroy | Fieldfisher
Skip to main content
Professional background

Professional background

I have acted in all divisions of the English High Court including the Court of Appeal and Supreme Court and my cases almost always involve international elements. I have been involved in LCIA, ICC, LME, LMAA, LCAM and ad hoc arbitrations - involving parties in various different jurisdictions - and in several ICSID arbitrations. I have also acted in cases before the Courts of the British Virgin Islands.

I am currently acting on a variety of commercial disputes including cases involving major global banks and international energy providers. I also have extensive experience of acting for and against groups of claimants, ranging from defending clients on claims being brought by groups of individuals, to advising groups of bondholders and institutional shareholders.

I have twice been the partner responsible for the cases recognised by The Lawyer’s Top 20 Litigation of the year surveys. Back in 2016, I was the lead lawyer representing the successful claimants in the first case to reach a judgment in the London High Court’s new Financial List. I have also acted in regulatory investigations involving both the Financial Conduct Authority and the Securities and Exchange Commission.

My diverse client base includes major domestic and international companies including clients in the sports, travel, financial and energy industries, as well as private equity houses, insolvency practitioners and individuals.

I was elected Vice President of the London Solicitors Litigation Association in early 2024 and appointed Vice President of the Litigation Commission of the UIA International Association of Lawyers in late 2024.

Notable deals

Notable deals

Advice on sponsorship

Advised on Olympic‑cycle (Tokyo) sponsorship arrangements for rights‑holders/brand partners.

Commercial Arbitration Dispute

Lead lawyer in a fast‑tracked ICC (London seat) commercial arbitration concerning major infrastructure contracts; achieved a final award within six months of the Terms of Reference (Bastion Infrastructure Group Inc.).

Covid related sports renegotiations

COVID‑era renegotiations of sponsorship/event contracts (variation, force majeure, performance) across football and wider sports.

Cross-Border English Law Dispute

Acting for a secured lender in a €100m cross‑border creditor‑priority contest on an English‑law loan; prepared pre‑emptive options against rival claims in the UK, Ireland and Luxembourg (Goldman Sachs Asset Management).

FOS Complaint Dispute

Advising on an FOS complaint alleging irresponsible lending and addressing proper‑respondent status; assessing affordability evidence and potential systemic exposure (CitiFinancial Europe Bank Limited).

Fraud, Warranty and Regulation Dispute

Advising a PE investor on acquisition‑related fraud, warranty and regulatory breaches involving a major waste business; multi‑disciplinary pre‑action strategy across tax, property and employment (CCJSH Ltd / Continuance Capital).

Professional Negligence and Fraud Dispute

Acting for a Luxembourg investment fund in a professional negligence/fraud dispute concerning advisory/management arrangements; quantifying losses and leading outcome‑focused negotiations (LNO Pix Group / Cyanstone).

Sponsorship and Endorsement Dispute

Sponsorship and endorsement disputes for clubs and elite athletes, including instructions for New Balance Athletic.

Structured Product Insurance Dispute

Advised on a structured‑product issuance error that inadvertently created a UK‑situs asset for a non‑dom HNW client; designed a discreet, low‑risk fix with the issuing bank and end‑client (Pictet & Cie (Europe) SA).

Urgent Injunction

Openwork v Capricorn (publishable): Defeated an urgent interim injunction in the London Circuit Commercial Court; continuing to defend and coordinate strategy alongside regulatory/employment workstreams (Openwork Limited).

Awards & recognition

Awards & recognition

Chambers 2024

John McElroy is a safe pair of hands and gives good, clear advice. John is an exceptional lawyer, he has excellent commercial instincts and he is very client-focused.

Legal 500 2024

John has significant experience in fraud and energy linked banking disputes.

Legal 500 2024

John is a polished operator. He keeps a keen eye on client objectives and effectively delivers.
 

Legal 500 2024

John is a plugged-in, commercial, astute and engaged partner.

Banking Litigation respondent

John is very easy to work with, always attentive and knowledgeable in his area.

Banking Litigation respondent

John is a very thorough partner with a great depth of legal knowledge and is also very commercially aware.

Legal 500

Relentless hard-worker’ John McElroy joined the practice from Hausfeld & Co LLP in July 2024.

Authored pieces

All Resources
Dispute Resolution
Insight

High Court dismisses professional negligence claim as abuse of process

24.08.2026
The High Court has dismissed a former Premier League footballer’s negligence claim against his former solicitors, finding that the claim had already been adjudicated, was an abuse of process and, in any event, was time-barred.
Learn more
Press Release

Fieldfisher boosts Disputes and Energy offering with partner hire Richard Power

01.06.2026
Learn more
A digital art piece featuring a futuristic and abstract design with bright white light at the center, radiating purple and blue hues. The composition includes dynamic lines, dots, and patterns resembling waves, giving a sense of motion and energy.
Dispute Resolution
Insight

Fieldfisher recognised in the GAR 100 for the fifth consecutive year

08.04.2026
Learn more
Dispute Resolution
Insight

Felipe Massa’s £64m claim over 2008 F1 title clears initial legal hurdle

11.02.2026
Learn more
Dispute Resolution
Insight

A second bite of the cherry denied: Precedent and the requirement to litigate fully

21.01.2026
The Commercial Court has recently engaged in a rare discussion of precedent in Frost v Giddens [2025] EWHC 3325 whereby the Defendant successfully applied to strike out the Claimants' claim as an abuse of process, and reminds parties of the importance of presenting their whole case on one occasion.
Learn more

What others say…

Chambers 2024

John McElroy is a safe pair of hands and gives good, clear advice. John is an exceptional lawyer, he has excellent commercial instincts and he is very client-focused.

Legal 500 2024

John has significant experience in fraud and energy linked banking disputes.

Legal 500 2024

John is a polished operator. He keeps a keen eye on client objectives and effectively delivers.