John Wyn Williams

Call 1992

“He is courteous and respectful to his clients and solicitors alike, a real team player. I can find nothing to be critical of.”

Legal 500 2022
Photo of John Wyn Williams

Practice Overview

John is a senior regulatory barrister. He has acted for a number of companies and Local Authorities dealing with a wide range of regulatory issues. His practice includes a number of high profile environment prosecutions, and he has acted for the Environment Agency and companies in air pollution and waste cases. He has an in-depth knowledge of water pollution cases.

John is also a senior criminal practitioner who defends and prosecutes serious matters in the Crown Court. He has defended and prosecuted homicide and serious rape cases and has a wealth of experience in dealing with complex historical sexual allegations. He is particularly expert at dealing with children and vulnerable adults. He is on the CPS Specialist Rape Panel.

He has defended and prosecuted serious and complex drug conspiracies and is adept at dealing with telecoms and cell-site analysis. He led for the prosecution in a recent case dealing with firearms shootings between rival gangs in Merseyside. Analysis of complex DNA evidence and statistical evidence presented by Professor Balding led to the convictions of four members of the gang for possessing a sub-machine gun and discharging a Colt .45 with intent to endanger life.


General crime

Successfully resisted Reference by the Attorney General
In April 2019, John appeared before the Vice President of the Court of Appeal Criminal Division Lady Justice Hallett responding to a reference made by the Attorney General’s office in relation to a sentence imposed on his client by HHJ Kershaw at Wolverhampton Crown Court. His client received a suspended sentence at the sentencing hearing in February this year. She was sentenced for her part in Operation Poppett which involved a Conspiracy to Supply Cocaine on an Industrial scale. Benzocaine was imported from China in industrial quantities. John was instructed by Bridgette Hibbert of Farleys in Preston.

Operation Marquette
John has been instructed in this complex and interesting gross negligence manslaughter where he represents one of the defendants charged with having a loaded shotgun in public when he was sat in the back of a land rover when the firearm discharged and killed a fellow passenger. Those charged with manslaughter were represented by silks and a legal argument was presented to the Judge on the basis that he had no “immediate control” over the firearm. Instructed by Andrew Scott of Parry Davies Solicitors in Bangor.

Operation Heathbird
John has been instructed to prosecute this case which alleges Possession of a magnum firearm and live ammunition with intent to endanger life. The weapon and ammunition were discarded by the defendants in a public thoroughfare in central Manchester. A close analysis of DNA evidence and a thorough investigation by National Crime Agency officers has led to the apprehension of both defendants. John is instructed by the Organised Crime Division North of the CPS.

Operation Tamar
John has been instructed to defend one of three defendants charged with attempting to import firearms into the Country from the USA. The firearms include a Glock 9mm hand gun and ammunition. Masks and balaclavas have also been recovered from the premises of one of the defendants. The case involves covert surveillance and statements from Law Enforcement officers in USA. The trial will take place in Preston Crown Court.

Operation Wainscot
John has been retained to defend in forthcoming criminal proceedings relating to the procurement funding of a North Wales hospital. The allegation against his client is that he aided and abetted the main defendant. The case is described by the team Specialist Fraud Division as “complex”.
The main defendant is alleged to have wilfully misconducted himself to such a degree as to amount to an abuse of the public’s trust in the said defendant, namely by submitting or causing to be submitted to Welsh Government business cases which falsely misrepresented the true total outturn cost of the Ysbyty Glan Clwyd Main Redevelopment Project, without reasonable excuse or justification, Contrary to Common Law.

Operation Fraser
John is instructed by Cardiff County Council on behalf of the Wales Illegal Lending Unit to prosecute a “loan shark” who plied his trade for 20 years lending and collecting nearly half a million pounds from vulnerable borrowers. WIMLU is one of only three units in the UK set up by the Government to prosecute “loan sharks”.

Operation Zeus
John has recently been retained to defend in this Conspiracy to supply class A drugs involving the alleged activities of two organised crime groups along the North Wales corridor. The investigation includes covert surveillance, telephone evidence and covert listening devices. The trial will be heard in Caernarfon Crown Court.

Operation Rossi
John has been instructed to defend one of seven defendants charged with Conspiracy to Defraud. The Investigation relates to the activities of Express Motors and their directors and involves allegations of fraud in relation to concessionary fares paid by Gwynedd County Council.

Operation Ulysses
John has been instructed to defend in this massive Conspiracy to Supply class A drugs. The pages run into over 30,000 and the case is described as the biggest drugs case prosecuted in Wales. It involves defendants from Liverpool, North Wales and also from Mid and South Wales. It is to be heard at Swansea Crown Court.

Operation Funder
John is currently instructed in a 6 week trial in Leeds Crown Court which involves an allegation that three defendants conspired to defraud elderly and vulnerable members of the public to service and purchase both Dyson and Kirby vacuum cleaners. It was alleged that a company owned by the Main defendant had benefitted to the tune of £1.5million.
The Case is brought by Yorkshire Trading Standards and was investigated by”Scambusters”.
John is instructed by Farleys of Preston and appears for the main defendant.

Operation Cobweb
John has received instructions to appear in a massive mortgage and money laundering case in Manchester. The matter is listed for a 12 week trial at Manchester Crown Court and he will be led by John Jones QC.
He is instructed by Forbes of Preston.

Operation Astute
Class A Drugs conspiracy involving detailed telecoms evidence- defending.

Operation Yonside
Class A and B Drugs conspiracy – acting for the main defendant with extensive telecoms evidence in excess of 30,000 pages.

Operation Measure
Defending in a multi handed drugs conspiracy with over 30 defendants.

Operation Ralston
Defending a defendant in a conspiracy to defraud involving £800,000 of public money.Operation Oriel
Recently instructed to defend a fireman and landlord charged with five counts of gross negligence manslaughter based on alleged Breaches under the Regulatory Reform (Fire Safety) Order 2005.

Operation Affleck
Recent instructions to defend in a multi handed conspiracy to defraud in an alleged £3.5m land bank fraud.

R v France
Prosecuting – Prisoner on day release helped with robbery of security guard in bank. story-14054558-detail/story.html

R v Ian Maxwell
Defended Falklands war veteran accused of 7 counts of fraud against elderley victims.

R v Robert Sullivan
Prosecution. Defendant admitted 25 sex charges including 9 rapes.

R v Gwilym Roberts
defended councillor charged with stabbing his wife. room-political-rival-jailed.html

R v Iestyn Davies
Six week murder led by P Harrington QC – including complex DNA and SOIL Analysis evidence.

R v Alwen Jones
Three week murder led by Mr I Murphy QC – involving issue of loss of control.

R v Gardiner
Manslaughter prosecution involving causation issues. manslaughter-ellesmere-6998083

R v Ken Jones
Manslaughter – defendant acquitted of killing his father.

Operation Kalina
Drugs conspiracy for CCU involving detailed telephone evidence. ref=var_0

Operation Base
Drugs conspiracy for CCU involving gangland warfare, guns and live ammunition.

Operation Knock
Drugs conspiracy.

Operation Justice
Large drugs conspiracy in North Wales. Rape prosecutions involving children and vulnerable adults. sentence.aspx

R v Newcombe-Buley
Child abuse. adopted-children RSPCA prosecutions.


Recently advised a leading UK commercial vehicle body and trailer manufacturer on Statutory Nuisance Proceedings brought by Trafford Metropolitan Borough Council Represented “Castle Cement” in proceedings involving air pollution and a risk to human health. Case was resolved by expert evidence confirming there was no risk. Instructed by Osborne Clarke solicitors.

Prosecuted BNFL for water pollution.

Prosecuted Welsh Water for breaches of Consents of water abstraction.

Prosecuted Kronospan PLC for pollution cases.

Defending a Rhyl businessman for depositing controlled waste and the ensuing POCA proceedings.

Advised Wrexham County Council on proceedings against a leading company for potential Statutory Nuisance Proceedings for air pollution.

Advised Pendle County Council in relation to odour pollution and Statutory Nuisance.

Appeared on behalf of a businessman in the building and construction field in a “Controlled Waste” case.
John is an enthusiastic member of UKELA and has a keen interest in the environment and the countryside. He has appeared in a number of cases involving the Forestry Commission, The Countryside Council, Defra and the Food Safety Agency.