John Platts-Mills

John is a natural and persuasive advocate, with a busy court and tribunal based practice. As well as running his own portfolio of cases he is regularly instructed as junior to more senior juniors and silks in Chambers.

He possesses a “first class mind”, which allows him to develop a command of complex issues quickly. As observed by one of his clients: “in addition, and what is not apparent on his barrister profile (where he looks very corporate), are his interpersonal skills”, which enable him to relate to and communicate with his clients easily and effectively, while The Legal 500 2025 Guide noted that John "has a great manner with clients, cutting through to the nub of the issue very quickly".

Before joining the Bar, John worked in the Shell Global Litigation team, where he had conduct of a range of international trade, distribution and investment disputes. He also has experience of complex international group claims and jurisdictional disputes, having worked on Okpabi v RDS in the High Court and Court of Appeal.

Before retraining as a lawyer, John worked as a corporate finance analyst in Deutsche Bank’s mergers and acquisitions team. He worked on a number of high-profile transactions, including: the Dixons Carphone merger and the IPO of Infinis.

• Recommendations

  "He is brilliant. He's really on top of the detail and is very empathetic. He has strategic nous and drafts pleadings really quickly." - Employment, Chambers UK 2025

  "John provides excellent client care. He is very quick to respond to client queries and provides legal positions with thorough expert advice." - Employment, Chambers UK 2025

  "John is a confident and capable advocate who is very good 'in the trenches'. He is able to be calm and polite yet very robust at the same time." - Employment, Chambers UK 2025

  "John is a superstar in the making." - Personal Injury, Chambers UK 2025

  "John has great attention to detail with all pleadings and is very experienced. He is an excellent advocate. He's very personable with all clients and adapts his style to make the client feel at home." - Personal Injury, Chambers UK 2025

  "He has a great manner with clients, cutting through to the nub of the issue very quickly. A talented and promising junior." - Employment, Legal 500 2025

  "I was very happy with how John represented our case and, in particular, his calm and reassuring demeanour." - Senior Lawyer, International Airline

  "I was very impressed and would not hesitate to use John again, really helpful, well prepared, professional and very user friendly." Paul Breen, Partner, JMW Solicitors LLP

• Employment

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  John is ranked as a leading Junior within Legal 500's 2025 UK Bar guide, as well as Chambers & Partners 2025 UK Bar Guide.

  John practises all areas of employment and discrimination law. He has a particular interest in appellate work; industrial relations; autonomous decision making; restraint of trade; and whistleblowing. John was invited to speak on industrial relations at the ELA Annual Conference in 2023 and is a member of the ELA working group responding to the Government’s AI white paper. He is currently completing the Said Business School: ‘Oxford Artificial Intelligence Programme’.

  In addition to regular appearances in the ET, recent case highlights include:

  • Riley v DL Insurance Services – EAT hearing listed summer 2023 following 3(10) hearing to address correct interpretation of dismissal for purpose of unfair dismissal; procedural unfairness; and discretion to extend time.
  • Shoker v Wolverhampton Homes – awaiting listing of full merits hearing in EAT, likely late 2023.
  • Secretary of State for Health and Social Care v Royal College of Nursing (2023): led by Andrew Burns KC, successfully sought a declaration preventing the RCN from taking unlawful strike action on 2 May 2023.
  • Geeks Limited v Watts: trial listed for summer 2023, acting for the defendant in ongoing litigation addressing the application of the doctrine of restraint of trade and the enforceability of training fee claw back clauses (instructed by the Good Law Project).
  • Smith v Tesco Stores Ltd [2023] EAT 11 successfully opposed appeal: persuaded the EAT that the employment tribunal correctly held that the claimant had acted in a manner that was scandalous, unreasonable or vexatious, concluded that a fair trial was no longer possible and decided it was proportionate to strike out the entire claim.
  • Trade Union v Employer (2023): advising multinational organisation about section 145B risks (junior to Andrew Burns KC).
  • Former Employees v Law Firm (2023): instructed by a law firm in relation to discrimination and whistleblowing claims brought by former fee earner.
  • Employer v Trade Union (2023): advising multinational organisation about interpretation of collective agreements and extent of liability to pay contractual redundancy (junior to Andrew Burns KC).
  • Fenniche v Kuwait Health Office and The Government of the State of Kuwait (2023): successfully represented the claimant in a complex discrimination claim engaging questions of state immunity. A remedy hearing is listed for 2024 with damages claimed in excess of £750,000.
  • Jonson v B&M (2023): successfully opposed appeal in the EAT against the Registrar’s decision not to extend time for lodging an appeal.
  • International consultancy v former employee (2022): advising employer in relation to enforceability of restrictive covenants and seeking injunctive relief.
  • Trade Union v Employer (2022): advising transport company in relation to potential injunctive relief, issues arising out of Mercer v Alternative Futures Group Ltd and section 145B liability (junior to Andrew Burns KC).
  • Investigation into allegations of discrimination made against NHT Trust (2022): assisting Georgia Hicks.
  • Investigation into allegations of discrimination made against commercial gallery (2022): assisting Lucinda Harris

• Personal Injury

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  John is ranked as a leading Junior within Chambers & Partners UK Bar Guide 2025.

  Ongoing and recent litigation:

  • Rugby concussion group litigation (ongoing): junior to Susan Rodway KC, Shaman Kapoor, Stuart Brady and Emma Corkill
  • Huntercombe Hospital litigation (ongoing): junior to Niazi Fetto KC, Prof. Conor Gearty KC, Peter Edwards and Stephen Cottrell
  • Catastrophic restraint (ongoing): junior to Stephen Killalea KC and Peter Edwards
  • Catastrophic RTA (ongoing): junior to Susan Rodway KC
  • Serious injury falling tree (ongoing): instructed by Irwin Mitchell London.
  • Catastrophic RTA (ongoing): junior to Christopher Walker
  • Catastrophic construction accident (ongoing): junior to Stephen Killalea KC
  • Serious injury workplace circular saw (ongoing): instructed by Irwin Mitchell London
  • Catastrophic wakeboarding accident (ongoing): junior to Stephen Killalea KC
  • FAA workplace (ongoing): instructed by Irwin Mitchell Bristol
  • Ronngard v Davies (2023): instructed by Dunne and Co, successful appeal and re-trial for cyclist struck by a vehicle emerging from a side road
  • Client v Insurer (2023), instructed by Pickering and Butters, secured a settlement in the region of £800,000 for a client who suffered life threatening injuries in an RTA
  • Inquest motorcycling accident (2022)
  • Inquest (2022) aortic dissection

• Insurance & Reinsurance

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  John is regularly instructed on a range of Insurance and Reinsurance disputes. He assisted Colin Edelman KC and Andrew Burns QC draft the Third Edition of the Law of Reinsurance.

  Recent highlights include:

  • Advising 2nd XS insurers in relation to aggregations issues arising out of SRA standard terms (junior to Andrew Burns KC) (2023)
  • Advising multiple litigations in relationt to potential contractual claims against a social media platform (junior to Richard Harrinson) (2023)
  • Instructed on a series of advisory briefs, led by Richard Harrison, in relation to issues arising from the Covid-19 pandemic and business interruption (2022)
  • Advising insurers in relation to aggregation issues arisingout of SRA standard terms (junior to Andrew Burns KC) (2022)Junior to Richard Harrison in relation to a coverage dispute under a product liability policy following the sale of allegedly defective adhesive (2021)
  • Junior to Richard Harrison advising in relation to the scope of a professional liability policy issued to a financial institution, concerning proper construction of insuring clause (2021)
  • Junior to Richard Harrison advising on coverage and notification issues in relation to a professional liability policy issued to a private medical practice (2021)
  • Being led by Richard Harrison in a complex High Court product liability dispute (2022)
  • External advisor to the FCA team in the Business Interruption test case litigation (2020)
  • Assisting Colin Edelman KC and Richard Harrison, in the preparation for the Supreme Court hearing in R & S Pilling t/a Phoenix Engineering Limited v UK Insurance Limited [2019] UKSC 16.
  • Assisting Andrew Burns KC in Allianz Insurance Plc v Tonicstar Ltd [2018] 1 Lloyd's Rep 38 – construction of agreement in relation to necessary qualifications of arbitrator.
  • Assisting Richard Harrison in Catlin Syndicate Ltd v Weyerhaeuser Co [2018] EWHC 3609 (Comm) anti-suit injunctions, incorporation of an arbitration clause and construction of an excess layer insurance policy.

• Commercial Litigation and Disputes

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  Building on his experience as a member of the Shell Global Litigation team, John has experience of litigation in both the courts and arbitration. He regularly accepts instructions in respect of a wide range of contractual disputes.

  Recent highlights include:

  • Currently being led by Richard Harrison in a complex High Court product liability dispute.
  • Assisting Andrew Burns KC in drafting an advice in relation to an aggregation clause.
  • Currently being led by Alice Mayhew KC in a High Court dispute concerning breach of restrictive covenants and breach of confidence.
  • Assisting Colin Edelman KC and Richard Harrison, albeit at a late stage, in the preparation for the Supreme Court hearing in R & S Pilling t/a Phoenix Engineering Limited v UK Insurance Limited [2019] UKSC 16.
  • Successfully establishing the validity of a settlement agreement in a two-day trial of a preliminary issue.
  • Advising a client alongside Andrew Burns KC as to the prospect of pursuing the executor of a deceased defendant.

• Clinical Negligence

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  John accepts instruction across the full range of medical disciplines. John is currently instructed to represent the family in an inquest into the death of a patient who suffered an aortic dissection.

• Investigations

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  John’s experience includes working on the following investigations:

  • Investigation into alleged whistleblowing at fintech business (2023)
  • Investigation into alleged discrimination at law firm (2023)
  • Investigation into allegations of discrimination made against NHT Trust (2022)
  • Investigation into allegations of discrimination made against commercial gallery (2022)