Jonathan Cook accepts instructions across Chambers' core practice areas.

He is frequently instructed in complex and high-value whistleblowing and discrimination cases in the Employment Tribunal, acting for both Claimants and Respondents. He often acts against more senior opponents, including KCs.

Jonathan has particular expertise in worker status claims and has recently acted, led by Jason Galbraith-Marten KC, for multinational Respondents in two group worker status cases brought by several thousand total Claimants.

He has developed an extensive appellate practice and has frequently appeared successfully as sole counsel in the EAT, often against more senior opponents up to KC level.

Jonathan also undertakes complex advisory work. Recent work includes advising an international airline on the correct approach to calculation of holiday pay across its workforce and advising a large multinational company operating in the gig economy on worker status and related issues.

Jonathan also acts for Claimants in multi-track personal injury and clinical negligence cases. He has been instructed in high-profile personal injury litigation, including as junior Counsel (led by Michael Rawlinson KC and Daniel Lawson) in High Court claims brought by firefighters injured in the Grenfell Tower fire.

Before coming to the Bar, Jonathan undertook a PhD in Politics and International Studies at the University of Cambridge, where his research focused on US politics and foreign policy during the Cold War. He combined his studies with a career as an international track and field athlete, representing England at senior international level in the 800m and finishing 6th in the 1500m at the 2016 UK Olympic Trials.

Currently, Jonathan referees rugby union at professional level for the RFU in the Gallagher Premiership, Premiership Women’s Rugby and RFU Championship.

Inns of Court

Gray's Inn, David Karmel Entrance Award for the GDL (2014)

Gray's Inn, Bedingfield Scholarship for the BPTC (2016)

University of Cambridge

Jesus College Foundation Scholarship (2008)

Sir James Knott Bursary (2009)

CHESS PhD Scholarship (2010)

Sir Arthur Marshall Scholarship (2013 and 2014)

Research Awards Gerald R. Ford Foundation Scholarship (2009)

Dwight D. Eisenhower Foundation Scholarship (2011)

Northumbria University

Ward Hadaway Prize – best GDL performance by a distance learning student (2015)

Bond Dickinson Prize – best overall GDL performance (2016)

Northumbria Law School Ben Hoare Bell Contribution Roll (2016)

Trinity Chambers Prize – best overall BPTC performance (2017)

Zenith Chambers Prize – best BPTC performance in Opinion Writing (2017)

Northumbria Law School Dean's Award for the BPTC

Industrial Law Society

Personal Injuries Bar Association

Employment Lawyers Association

Chambers & Partners 2025: (Employment) "Jon is someone that I would recommend without hesitation."

"He is a pleasure to deal with, highly responsive and strategic."

"Jon has outstanding client care skills and is highly regarded by clients."

"Jonathan's cross-examination and document management in court is especially good."

Legal 500 2025: (Employment) “His mastery of the law in action is really impressive as is his preparation.”

Chambers & Partners 2024: (Employment) “Jonathan Cook is a reputable choice of counsel acting for both claimants and respondents in employment disputes. He is adept at handling disability discrimination and constructive dismissal claims, with notable experience across the Employment Tribunal and the Employment Appeal Tribunal.”

“Jon is simply superb in really difficult tribunal matters. His cross-examination and advocacy brings out exactly the characteristics which go a long way to proving cases."

"He is very polished, on the detail and all over the documents. He is an incredibly efficient advocate, never misleading on his points."

"Jon sets out his arguments clearly and thoroughly; he writes impressive submissions. He assists his clients with strong advocacy, being composed and confident."

BA, History, University of Cambridge, 2008 (First Class)

MPhil, Historical Studies, University of Cambridge, 2009 (Distinction Equivalent)

PhD, Politics and International Studies, University of Cambridge, 2015

GDL, Northumbria University, 2016 (Distinction)

BPTC, Northumbria University, 2017 (Outstanding)

Chapters on "Proof of Negligence" and "Human Rights" in Lewis and Buchan (eds.), Clinical Negligence: A Practical Guide (2019)

"Morrisons' Liability for Rogue Employee: an Apple of Discord", PLC Magazine, December 2018

Employment and Discrimination

Appellate Cases

Oyebisi v Hyde Housing Association Ltd [2024] EAT 124 – Notice requirements for strike out applications in the Employment Tribunal.

Minis Childcare Ltd v Hilton-Webb [2024] EAT 108 – Proving objective justification in indirect discrimination claims.

Riley v Direct Line Insurance Group Plc [2023] IRLR 952, EAT – Represented the successful Respondent. The EAT considered the principles governing termination of an employment contract by mutual agreement and the circumstances in which an Employment Tribunal may be entitled to vary reasonable adjustments for a disabled litigant which were agreed at an earlier case management hearing.

Vashishtha v NHS England and others [2023] EAT 44 – Successfully acted for a Respondent GP Practice in complex and long-running disability discrimination claims brought by a former trainee GP. Secured a rare order that the Claimant/Appellant pay the Respondents’ costs of the EAT proceedings. Appeared as sole Counsel against a KC.

Ministry of Justice v McGrandle [2022] EAT 126 – Represented the Claimant retired part-time Judge in an appeal in which the EAT considered the correct approach to reconsideration when a claim has been dismissed upon withdrawal. Upon remittal, the Employment Tribunal was persuaded that a fresh claim on the same facts would not be an abuse of process and granted a fourteen-year just and equitable extension of time to allow the new claim to proceed.

De Lacey v Wechseln Ltd t/a Andrew Hill Salon [2021] IRLR 547, EAT – Acted for the successful Claimant/Appellant in a case which clarified the causation test in discriminatory constructive dismissal claims.

Jagex Ltd v McCambridge [2020] IRLR 187, EAT – Successful representation of the Claimant in the EAT. Resisted the Respondent's appeal against the Employment Tribunal's approach to contractual construction and findings on wrongful dismissal and Polkey. A narrow point on contributory conduct was remitted to the same Tribunal.

Sanha v Facilicom Cleaning Services Ltd UKEAT/0250/18 – Successful remedy appeal on behalf of the Claimant. The EAT substituted a finding that the Claimant was entitled to his compensatory award without any reduction for contributory conduct or failure to mitigate. The Respondent's cross-appeal was dismissed.

First Instance Cases

Various Claimants v Amazon UK Services Ltd and others – Acting for Amazon (as junior to Jason Galbraith-Marten KC) in group worker status litigation.

Various Claimants v Ola UK Private Ltd and Ola Netherlands BV – Acting for the Respondents (as junior to Jason Galbraith-Marten KC) in group worker status claims brought by drivers against the operators of an app-based ride hailing platform.

A v P – Acting for a Respondent start-up in whistleblowing and victimisation claims brought by a former senior employee. The pleaded value of the claim exceeds £1 million.

Anklesaria v Trinity College Cambridge – Successful representation of the Respondent Cambridge University College in race discrimination and victimisation claims brought by a current employee.

Boswell v Starspeed Training Ltd – Representation of the successful Respondent in complex whistleblowing claims brought against a helicopter training company by a senior pilot.

X v Y – Succeeded at trial on liability in a disability discrimination claim for a Claimant who suffered an exacerbation of his PTSD due to the Respondent's handling of a redundancy process. Substantial six figure settlement prior to the remedy hearing.

W v H – Junior Counsel for the Claimant (led by Tom Croxford KC and Andrew Short KC) in complex and high value whistleblowing, unfair dismissal, discrimination and equal pay claims brought by a former senior EMEA executive against a US-headquartered multinational.

R v S – Junior Counsel (led by Paul Gilroy KC) acting for the former chief executive of a professional football club in a multi-million pound claim and counterclaim in the High Court.

Kul v Home House Ltd – Successfully represented the Claimant in a disability discrimination and unfair dismissal claim which involved a number of complex legal issues, including the applicability of the doctrine of frustration in cases of long-term absence. Respondent represented by King’s Counsel.

Personal Injury and Clinical Negligence

Grenfell Tower Litigation – Instructed as second junior (led by Michael Rawlinson KC and Daniel Lawson) in High Court personal injury claims brought by a large group of firefighters injured in the Grenfell Tower Fire.

X v A Chief Constable and a Vehicle Manufacturer – Fatal Accidents Act claim brought by the dependents of a police officer who died on duty due to alleged failures in the manufacturing and maintenance of a police vehicle. Led by Michael Rawlinson KC.

G v Private Transport Provider and an NHS Trust – Acted for an elderly NHS patient who sustained multiple serious injuries during transportation to hospital. Successful settlement.

G v Cleaning Company and an NHS Trust – Acted for an employee who sustained serious lower limb injuries after slipping on a wet floor. Successful settlement.

X v An NHS Trust – Represented the Claimant in a claim where negligently performed gynaecological surgery had caused infertility. Successful settlement.