John Warrington

Year of Call: 2000

‘Surgical in his approach to cases, he can ingest large volumes of evidence. ’

The Legal 500 2020

Our specialist clerks can be contacted by email on or phone on 020 7332 5400. To contact our Chambers Director directly in relation to a specific members’ practice, please email

“He delivers excellent results.”

Chambers & Partners 2024.

"John brings attention to detail and thoroughness. A persuasive advocate."

The Legal 500, 2023

"A highly talented advocate. He works incredibly hard, and combines good judgement with an eye for detail."

The Legal 500, 2022

"Dedicated in his preparation and proactive in his approach to matters."

The Legal 500, 2022

John has a good courtroom manner and approaches issues with sensitivity.'

The Legal 500 2024.


John is a barrister specialising in public law, crime, regulatory law and professional disciplinary proceedings.  Within these fields, his principal areas of interest include public inquiries, serious organised crime, high-value financial crime, environmental law, health and safety and the regulation of healthcare professionals, He is ranked as a leading criminal barrister at the London Bar in Chambers and Partners UK Bar Guide and The Legal 500.

“Brilliant with clients, highly knowledgeable and someone who always fights his corner.”

Chambers & Partners 2024.

"He is detailed in his case preparation and always stays in contact with instructing solicitors."

The Legal 500, 2022

"An effective advocate who understands the wider picture and provides clear and concise advice."

Chambers & Partners 2023, 2022 & 2021.

"John is a highly experienced barrister who has a great practice prosecuting and defending in criminal cases. Technically impressive and incredibly thorough in his preparation on cases. He has a light touch in court."

The Legal 500, 2021

Regularly instructed in cases of the utmost seriousness, John has acted in matters of homicide, serious violence, multi-million pound fraud, high profile corruption and large-scale drug trafficking.  His advisory work often involves instructions at the pre-charge or investigative stage.  He provides advice and representation to high-profile executives and performers within the music and entertainment industries, including Grammy and Ivor Novello award-winning recording artists.

Litigation relating to incidents arising from serious regulatory breaches, often involving corporate defendants, forms a significant part of John’s practice.  Latterly, he has defended and prosecuted a number of serious toxic sewage discharge cases, as well as acting in matters of risk to life health and safety breach and asbestos related offending.

John’s criminal law pedigree lends itself well to his increasing popularity in the professional disciplinary tribunals.  He often acts in sensitive cases involving tandem criminal and disciplinary issues, in particular those concerning professionals with substance misuse or mental health problems.  He is also experienced in matters related to serious clinical failings.  He has particular expertise in the dental and nursing professions.

John is currently acting as deputy first-junior counsel to a long-running and complex public inquiry.

Judicial appointments

  • Recorder (crime) - January 2022.
  • Fee-paid Judge of the First-tier Tribunal (Social Entitlement Chamber) (2019-2022).

Additional Information

In addition to his busy practice, John is a qualified advocacy tutor and regularly lectures and provides training on various aspects of his core practice areas.

Professional panel appointments

  • List of Specialist Regulatory Advocates in health and safety and environmental law (List B).
  • General Dental Council (GDC) appointed advocate: Band C (10 years' call and above).
  • The Bar Standards Board (BSB) panel.
  • The London Boroughs Legal Alliance panel (Band A).
  • Crown Prosecution Service advocate panel, including the specialist Fraud, Proceeds of Crime and Serious Crime panels.

Direct Public Access:

  • John is qualified to accept instructions by way of Direct Public Access.

Criminal Defence

John is ranked as a leading criminal barrister at the London Bar in Chambers & Partners UK Bar Guide and the Legal 500.

His practice incorporates a broad range of offending, including homicide, serious organised crime, large-scale drug trafficking, people trafficking, firearms, serious violence and public order, dishonesty and sexual offences.  John has particular expertise in health and safety and environmental offending.  He undertakes a significant quantity of privately instructed criminal defence work.

John is an experienced appellate lawyer, including referrals to the Court of Appeal by the Criminal Cases Review Commission.

Criminal Prosecutions - Private & Public

John is ranked as a leading criminal barrister at the London Bar in Chambers & Partners UK Bar Guide and the Legal 500.

Whilst historically a defence advocate, John also prosecutes and has been appointed to the Crown Prosecution Service Advocate Panel (Level 3), including the specialist Fraud, Proceeds of Crime and Serious Crime panels.

As a prosecutor, John’s private instructions are varied, including fraud, infringement of intellectual property rights, animal cruelty, health and safety and environmental offending.

Business Crime & Financial Regulation

For most of his career, John has specialised in complex fraud, corruption, and money laundering.  He receives pre-charge instructions, both on behalf of the authorities and suspects.  He is experienced in all types of fraud, including those involving tax, government, public bodies, charities, financial services, and carousel fraud.  John has acted in several cases that have attracted widespread national media interest.

Asset Forfeiture, Confiscation & Civil Fraud

John is regularly instructed in high-value confiscation proceedings, including multi-million-pound matters.  He is also experienced in restraint, cash forfeiture, condemnation proceedings and production orders.

Professional Discipline & Regulatory

John has a broad professional disciplinary and regulatory practice, acting on behalf of regulators and registrants, as well as large corporate clients.  His core areas of practice are healthcare, environment and pollution, health and safety, hallmarking/jewellery trade and haulage, although he is experienced in many other fields.  He is frequently instructed to appear before various committees, tribunals and senior courts, particularly in cases of sensitivity.

John has been appointed to the List of Specialist Regulatory Advocates in health and safety and environmental law (List B), the General Dental Council panel, the Bar Standards Board panel and the London Boroughs Legal Alliance panel (Band A).

Inquests & Inquiries

John accepts instructions in relation to public inquiries and inquests.  In this context, he is particularly experienced in drafting detailed requests for evidence, applications for restriction orders and various aspects of privacy.

Professional Memberships

  • Association of Regulatory and Disciplinary Lawyers.
  • UK Environmental Law Association.
  • Fraud Lawyers Association.
  • Criminal Bar Association.
  • South Eastern Circuit.
  • North London Bar Mess.
  • Kent Bar Mess.

Cases of Note


R v H; R v P; R v Robertson; R v S; R v Dan; R v Walker; R v W; R v F [2011] EWCA Crim 2753; [2012] 2 All E.R. 340; [2012] Crim. L.R. 149; Times, December 9, 2011.

CCRC referral. Guidance as to the correct approach to sentencing in respect of historic sexual offences.

R v H; R v D; R v Chaudhury [2009] EWCA Crim. 2485; [2010] 3 Crim. L.R. 246; 1 Archbold Review, February 5, 2010.

Court of Appeal guidance re text procedures and the statutory regime for sentencing discounts for informants pursuant to the Serious Organised Crime and Police Act 2005.

R v. B & Others


R v. C & Another

Lifer attempted murder at Category A prison.

R. v. M

Death by dangerous driving.

R. v. H & Others

Largest Class A drugs seizure (£7 million) in East Midlands

R. v. B & Others

Multi-jurisdiction importation of £5 million of cocaine.

R. v. I & Others

Sophisticated cocaine and heroin “takeaway delivery” service.

R. v. G & Others

Organised national trafficking of Class A and B drugs.

R. v. G & Others

Importation of three tonnes of cannabis.

R. v. M

Triad cannabis factories yielding £1 million of product per annum.

R. v. H & Others

Joint Triad/Russian venture involving organised prostitution of trafficked females.

R. v. C & Others

Series of armed robberies.

R. v. K & Others

Sophisticated immigration deception.


General Dental Council v. E

Undertaking procedures beyond professional competence.

General Dental Council v. W

Substance misuse and offending.

General Dental Council v. C

Alcohol misuse.

General Dental Council v. G

Extensive failed diagnoses and improper treatment.

Nursing and Midwifery Council v. K

Neglect of patient.

Health and Safety Executive v. R Limited

Asbestos exposure.

Environment Agency v. T Limited

Fish kill sewage discharge.

T Limited v. B Limited

Large-scale trade effluent discharge.

T Limited v. J Limited

Toxic levels of sulphide in sewerage network.

LB Hammersmith and Fulham v. T Limited

Summonses alleging regulatory breaches stayed for abuse of process.

M v. RB Greenwich

Prohibition order on premises posing serious fire risk.

RB Greenwich v. G Limited

Gross food hygiene breaches, including rodent infestation and food contamination.

R v. W Limited

Unlawful storage of explosives.

W v. LB Islington

Validity of £90 million worth of penalty charge notices.

LB Wandsworth v. T Limited

Hallmarking breaches re high-value gold stock.

Re A

Review of premises licence.

M v. Transport for London

Restoration of hackney carriage license on appeal.

T Limited v. A

Advising as to entry to obstructed land for major flood relief scheme.

T Limited v. RB Windsor and Maidenhead

Noise abatement notice re pumping station.

T Limited v. LB Hammersmith and Fulham

Warrants of entry for largest infrastructure project ever undertaken by UK water industry.


Re P

Application for production order in high-value money laundering investigation.

R. v. C

High-value proceeds of crime proceedings related to large-scale drug trafficking.

Metropolitan Police v. M

High-value cash detention proceedings.


R. v. W

£10 million finance fraud.

R. v. M & K

Pre-charge advice to Attorney General and subsequent prosecution of corruption related to government department.

R. v. P & Others

Multi-jurisdictional money laundering of proceeds of high-value fraud.

R. v. N

High-value breach of trust fraud committed over a decade.

R. v. K & S

High-value banking fraud.

R. v. D & D

Sophisticated high-value insurance fraud and money laundering.

R. v. C

High-value charity fraud committed by leader of local council.

R. v. H & A Ltd

Laundering proceeds of £13 million carousel fraud.

R. v. A & Another

Laundering proceeds of £2 million tax credit fraud.

R. v. K & Others

Laundering proceeds of carousel fraud.

R. v. M & Others

High-value NHS fraud involving trust directors.

R. v. G & Others

Serious corruption within major financial services provider.

R. v. U & Others

Multi-million pound money laundering via Middle Eastern “hawala” banking system.