Mark Harries KC

Call 1995 | Silk 2019


Mark specialises in business and financial crime, professional discipline and regulatory work, in particular in the medical legal , and financial sectors. An “outstanding advocate” with “gallons of charm” who is known for his “phenomenal way of cutting through to the heart of a case“, he provides a first class service for private client HNW individuals and corporate entities accused of fraud, serious crime and professional misconduct. He has “a brilliant mind and fearlessly fights his client’s corner” with a wealth of experience from criminal homicide and multi-million pound financial crime to professional misconduct of the most serious nature and inquests acting for individuals, corporate bodies and NHS Trusts.


Mark is clerked primarily by Lee Johnson, Clare Sabido, Jennifer Pooler and Emma Bell

Re JH: In 2022 Mark was instructed as leading counsel for an NHS Trust in a complex and sensitive maternal death inquest in which the Coroner was eventually persuaded that neither corporate manslaughter nor gross negligence manslaughter by a Trust employee was made out so a conclusion of unlawful killing was avoided.

“Mark is extremely intelligent and has an excellent ability to express complex matters in straightforward and logical terms. He is an exceptional advocate.”

The Legal 500, UK Bar 


In 28 years of practice at the Bar, Mark has acquired an outstanding reputation as a “razor-sharp, immaculate advocate” in a range of work that encompasses serious financial crime and fraud, all types of homicide and professional misconduct with a particular focus on the medical and healthcare professions.

Mark is renowned for his exceptional work ethic and refined, strategic approach to business crime, including white collar and corporate fraud, and for the care and sensitivity with which he deals with every client. Mark has a wealth of experience defending company directors and corporate bodies in cases alleging tax fraud, fraudulent trading and corruption at all levels and even in the most complex trial has “a phenomenal way of cutting through to the heart of a case.”

He is particularly sought-after to defend high net worth and high profile individuals accused of serious violence or sexual offences, where reputation as well as liberty is at stake. He “works tirelessly and meticulously to achieve the best outcome for defendants” in properly resourced cases of complexity and importance to individuals, their careers and their families. He is frequently privately instructed to provide pre-charge strategic advice, in relation both to anticipated criminal proceedings and related disciplinary or internal investigations.

Mark has a particular interest in dealing with matters of a clinical or pathological nature and the analysis of complex forensic scientific evidence which has led to his substantial experience acting in cases involving fatalities, both in the criminal and professional discipline fields.

He has appeared in many highly publicised murder trials and his medico-legal expertise is particularly impactful in cases concerning gross negligence and unlawful act manslaughter, including the successful defences of a police station doctor who failed to diagnose a drug overdose in a detainee and the extensively publicised case involving the commercial supply of a toxic slimming pill which caused the death of a young woman.

In his professional discipline and regulatory practice, Mark defends professionals accused of misconduct before a wide variety of regulatory bodies. He has acted for solicitors, surveyors, soldiers and teachers but his experience in the criminal courts cross-examining medical experts makes him especially effective in his representation of medical and healthcare practitioners, particularly when cases turn on matters of clinical criticism or involve fatalities. He has vast experience in representing doctors and paramedics whose clinical and wider conduct is criticised by the GMC and HCPC respectively, together with pharmacists, therapists, psychiatrists and nurse to name just a few.

That substantial experience translates into advantage in inquests and inquiries work where Mark’s sympathetic yet robust approach singles him out as an advocate adept at dealing with sensitive cases requiring calm leadership and authority, whether on behalf of individuals or organisations like NHS Trusts, particularly in cases where gross negligence or corporate manslaughter are central considerations.

Mark’s practice also extends to representing servicemen and women in HM Forces in the UK and abroad where he has successfully defended criminal allegations of every level of seriousness at Courts Martial and within internal Forces disciplinary processes.

In addition, Mark accepts instructions to provide advice in relation to appeals against conviction, sentence and by way of judicial review on a privately funded basis. He is an Advisory Panel member for Inside Justice, a charity which investigates miscarriages of justice and seeks to remedy them.

Business & Financial Crime

The 2022 Chambers UK Bar Guide describes Mark as a “very shrewd and smooth operator” who is “extremely hard working and a great tactician.” He is “excellent on his feet” and “his timing is perfect.” Prior to taking Silk in 2019, he was a consistently ranked as a leading junior in the fields of both financial crime and general crime.

He has significant experience defending prosecutions brought by the National Crime Agency, its previous guise as the Serious Fraud Office and HMRC, in particular allegations of tax evasion and banking and investment fraud. He has defended in MTIC frauds, Ponzi frauds and boiler room frauds across a wide variety of industries, including the diamond trade, the wine industry, environmental research and the construction industry in addition to  frauds within financial and investment markets.

Mark’s clients are usually high net worth professionals, CEOs, company directors, accountants and traders facing allegations of fraud, corruption or embezzlement, for whom criminal proceedings are desperately damaging on a practical and career level, whatever the outcome of a trial. Mark prides himself on going above and beyond in properly resourced cases so that he can met and exceed the high expectations of the most demanding of clients whose reputation is on the line.

Mark is committed to the meticulous and thorough preparation of every case in which he is instructed and is adept at handling cases involving a very large volume of paperwork, distilling the important issues into manageable and comprehensible topics to be presented to a jury with clarity and persuasion.

In recent years, Mark has presented seminars on a number of topics relating to financial crime, including the hallmarks of fraud, with a particular emphasis on hedge fund and banking fraud.

Recent business crime instructions of note include:

  • R v W (Southwark 2023): Leading for the defence in the highest value cryptocurrency money laundering trial ever prosecuted in the UK.
  • R v C (Wood Green): For the defence of a company director in a 6 month HMRC/Trading Standards prosecution alleging tax fraud committed by way of a diesel-bulking scam. DC was acquitted of over £1m worth of excise duty evasion prior to trial following evidential submissions made on his behalf causing a re-think of the prosecution case; at trial, he was acquitted of VAT evasion in respect of a company owing over a quarter of a million pounds of VAT and of that company’s fraudulent trading. DC was convicted of two lesser counts confined to a single company. Featured in the forthcoming BBC documentary “Defenders UK.”
  • R v C (Blackfriars): For the defence of one of 3 brothers in a 6 month trial of 10 defendants centring upon an £11m diversion fraud, using computer malware to obtain millions of email addresses which were systematically hijacked and used to conduct a variety of internet frauds.  For press coverage, please click here.
  • R v J (Derby): Acted for the first defendant, a solicitor, in a multi-handed 9 week trial who was alleged to have run a “cash for crash” fraud through his law firm. 5 of the 7 co-accused ran cut-throat defences against GJ. They were convicted. GJ was acquitted of all counts. For press coverage, please click here.

 Professional Discipline & Regulatory

Mark has extensive experience across a wide variety of regulatory bodies representing private individuals facing accusations of misconduct and fitness to practise impairment. He acts both at the final fitness to practise hearings and earlier in proceedings where interim orders are sought in respect of the most complex and serious allegations. He welcomes instructions at the investigation stage with a view to contributing to submissions that might avoid FTP proceedings entirely.

Early work involved presenting cases on behalf of the General Dental Council and for Lincoln’s Inn; Mark now acts only for the individual or corporate entity accused by their regulatory body and has defended a diverse spectrum of professionals including doctors, paramedics, pharmacists, therapists, solicitors, teachers and members of the Armed Forces.

He has particular expertise in the defence of those working in the medical and healthcare professions and has successfully protected the careers of a number of paramedics criticised by the HCPC following the deaths of patients in their urgent care.

He is adept at familiarising himself with complex clinical and technical issues within other professions and applying that understanding to cross-examination of the professional body’s experts, leading to him being much sought-after in the defence of doctors, paramedics and others providing front-line medical care.

More recently, Mark has acted in a number of cases involving the developing practice of online treatment, prescribing and dispensing of medication by doctors, pharmacists and corporate bodies following misconduct allegations brought by the GMC and the GPhC.

His criminal background makes him particularly effective in the defence of professionals accused of misconduct by reason of the commission of criminal offences, in particular fraud and sexual allegations made by patients or clients.

He has also appeared before the CQC on behalf of care homes when their standard of care is under scrutiny and in the Court of Protection as leading counsel in which robust and forensic cross-examination of psychiatric experts was required.

Mark was part of the legal team acting pro bono for Claire Matthews, a young solicitor struck off for covering-up the loss of case papers on a train, in her successful High Court challenge to the SDT’s decision to strike her from the Roll.

He has acted in a significant number of courts martial throughout his career; in a regulatory context, he recently successfully defended a very senior member of the Armed Forces in respect of a Major Administrative Action for which the recommendation was termination of service; that outcome was avoided.

Mark has previously written and delivered an advocacy training programme to the British Association of Social Workers, and spoken on a wide variety of topics including, most recently, dishonesty in regulatory proceedings for the “PLOD” podcast and sexual offences in professional discipline cases at the postponed Pharmacy Law and Ethics Association Annual Conference in February 2022.

A selection of Mark’s recent cases includes:

Murder and Manslaughter

Mark has been instructed in many highly publicised cases of homicide throughout his career, including the murder of a Linklaters solicitor, the double gangland executions of John & Joan Stirland and the assassination of “Celtic Pat” Marshall; the last two trials were written about extensively in book called “Hoods” by Carl Fellstrom.

He has also appeared in a number of trials concerning gross negligence manslaughter, including the successful defences of a police station FME who failed to diagnose a drug overdose in a detainee, a homeless drug user alleged to have supplied a fatal dose of heroin to his partner and the extensively publicised case involving the commercial supply of a toxic slimming pill which caused the death of a young woman.

Mark has been instructed in cases arising out of road traffic accident fatalities, including the successful defence of a Royal Mail lorry driver who hit a stationary vehicle on the A40, killing its elderly occupants, and appeared for 14 year old girl who kept her pregnancy secret from her parents in a rarely seen case of infanticide.

Mark is a highly effective cross-examiner of expert witnesses, which has led to increasing instructions in cases which turn upon forensic, expert opinion. His medical and healthcare regulatory experience makes him especially adept at taking on experts on medical issues, particularly on issues of pathology and causation.

A selection of homicide trials in which Mark has been instructed include:

In Silk

  • R v M (CCC 2023): Pending trial to defend a 16 year old boy accused of joint enterprise murder by stabbing.
  • R v B (Derby 2022): Pending trial for the defence of a man driving a tractor from which a trailer uncoupled and collided with a vehicle, killing an occupant.
  • R v F (Derby 2021): Defendant accused of sadistic torture and killing of a former partner.
  • R v J (Nottingham 2020): Defending an admitted drug dealer alleged with 5 others to have attacked a rival dealer’s drug house with machetes, killing one of the men as they tried to escape from first floor windows. At the time, the longest running trial during the Covid pandemic.
  • R v B (Derby 2020): For the defence of the alleged killer of a drug dealer in an ambush meeting on the pretence of a drug deal. Cut-throat with two other defendants accused of murder and conspiracy to rob, the defendant admitted presence at the scene but blamed his co-accused for stabbing the victim to death. The trial gave rise to complex admissibility issues, including evidence discovered on illegally held mobile telephones in prison showing the video to a grime video about the murder performed by the defendant. The Derby Telegraph.
  • R v A (Harrow 2020): For the defence of the 2nd defendant in an 8-handed murder trial arising from a road rage incident between two rival gangs, during which the defendant admitted killing the deceased with a samurai sword. The defendant contended that he was acting in self-defence and the defence of his brother. Trial aborted in week 3 due to Covid-19 lockdown.

Serious & Specialist Crime

Mark has 27 years of experience in defending individuals facing serious criminal allegations. Such is the importance of these cases to the defendants and their families, Mark now only accepts instructions on a privately funded basis so that he and his instructing solicitor are able to dedicate the time and resources necessary to ensuring that a fully-investigated and comprehensively prepared defence can be advanced and the defendant assured of the very best chance of securing the right verdict.

His aim in representing every client is to give them confidence and complete assurance that no stone will be left unturned in attacking the Crown’s case and advancing the Defence case. Mark is acutely aware of the anxiety and distress that criminal proceedings cause for those caught in the spotlight; he is renowned for his “first class client manner” and the assurance that his “cool, calm, collected” approach brings to a case. No stone is left unturned.

Often, Mark’s cases have a particularly sensitive element to them. He successfully defended a former Sandhurst instructor in the Operation Elveden prosecutions in which the defendant was alleged to have sold stories and photographs to a tabloid about Princes William and Harry during their time at the military academy. He also secured the acquittal of the former Police and Crime Commissioner of Northamptonshire accused of data breaches following the dissemination of confidential information to MPs and local counsellors about a police inquiry into the financial irregularities of a Conservative MP.

In cases alleging serious sexual assault, Mark has developed a sensitive yet firm and effective style in the cross-examination of vulnerable witnesses, with particular mastery of voluminous and complex unused material and third party applications in historic abuse cases.

Recent cases of note include:

  • R v X (Isleworth Crown Court 2023): acted for a senior and well respected chemical engineer facing criminal trial having inflicted near fatal head injuries to another man whom he struck repeatedly with a samurai sword in September 2020. A jury in August 2023 at Isleworth Crown Court acquitted the defendant of wounding with intent and another jury in July 2024 cleared him of the lesser charge of unlawful wounding following a second trial, finally bringing proceedings to an end. The defence case was that X acted in reasonable and proportionate self-defence, fearing that the man had come to burn down his house after a campaign of threats and harassment targeting the defendant and his family. The case was privately funded and although a costs order was made in the defendant’s favour to include his legal expenses, the rules limit his recoverable costs to legal aid rates; it serves as a reminder both of the benefits of a well-resourced, privately funded defence and the all-too-common injustice that an innocent man remains significantly out of pocket despite both juries’ favourable verdicts following nearly 3 years of anxious turmoil. Mark was instructed by Sadique al-Hakeem of Tuckers Solicitors.
  • R v X (Derby 2022): Instructed privately in the successful defence of a grandfather accused of historic sexual assault upon his granddaughter, then aged 7 and 8. Following a delay in reporting, by the time of trial the complainant was 15. Acquitted by the jury.
  • R v T (Birmingham 2022): Instructed privately by the family of a defendant accused of unlawful wounding in a university nightclub, having caused multiple facial fractures to a fellow student in pre-emptive self-defence. Acquitted by the jury.
  • R v MBB (Manchester): Operation Warbird – Leading for the defence of the Principal and director of Tier 4 private colleges accused of facilitating illegal immigration by running sham educational establishments to procure CAS from the Home Office for non EU migrants intent on evading immigration control. See press coverage in the Manchester Evening News.
  • R v AS (Southwark): The successful defence of a former Police and Crime Commissioner in an unprecedented prosecution for Data Protection Act breaches. Mr Justice Green described the trial as “very novel, sensitive and complex.”  Press coverage from BBC News.
  • R v JH (Central Criminal Court): Operation Elveden – the defence of a former Colour Sergeant at the Sandhurst Military Academy charged with misconduct in a public office. H became the only public official acquitted by a jury in this series of prosecutions.  See press coverage in The Guardian and The Evening Standard.

Military Law

Mark has defended in Courts Martial in the UK and in Germany in a wide variety of criminal allegations, including serious violence and rape. Most recently, he defended in these cases:

Army Board v X (Aldershot): Major Administrative Action against a senior ranking soldier. Termination of service avoided following submissions on culpability due to mental health fragility and the extent to which service in the Armed Forces is exempt from application of the Equality Act 2010.

R v M (Royal Navy Court Martial, HMS Nelson): A lieutenant serving aboard a Type 45 Destroyer in the Gulf, was accused of multiple rape and sexual assaults on 5 complainants of subordinate rank on the ship over a period of several months will the ship was alongside and on manoeuvres. Following a successful legal argument resisting the Crown’s application to render offences and complainants cross-admissible, the indictment was severed. Ultimately, the defendant was convicted of complaints made by a single complainant and acquitted of allegations made by the others.

Appeals and Miscarriages of Justice

Mark is an experienced appellate court advocate both in the Court of Appeal Criminal Division and the Divisional Court.

He has advised on judicial review in a number of criminal and human rights based matters, including the impact of prison officers’ industrial action on prisoners’ rights, the recovery of defendants’ costs orders and Parole Board decisions.

Mark accepts instructions on a privately funded basis to consider and advise upon potential appeals against conviction and sentence in recent and historic cases. He has been an Advisory Panel member of the charity Inside Justice since 2019.

Recently, he obtained leave to appeal conviction on behalf of an Inside Justice client previously convicted of drug importation and recently appeared in the Court of Appeal Civil Division for another client of the charity seeking to challenge the refusal by a police force to provide post-conviction disclosure in a murder case.


Mark has been consistently recommended by the legal directories as a leading practitioner and won the Pro Bono KC of the Year at the Advocate Pro Bono Awards 2022. Recommended for crime, financial crime and fraud, recent editorial includes the following:

  • offers fantastic client care;
  • Mark’s client care is exemplary;
  • an outstanding advocate with a wealth of experience of dealing with complex legal issues;
  • unwavering charm and professionalism;
  • an immaculate advocate;
  • there is not a single word he says which does not serve a purpose. He is excellent on his feet;
  • a very shrewd and smooth operator. He’s extremely hard-working and a great tactician. His timing is perfect and he is polite and persuasive on his feet;
  • Mark is extremely intelligent, and has an excellent ability to express complex matters in straightforward and logical terms. He is an exceptional advocate;
  • a charming silk who exudes confidence. He has a brilliant mind and fearlessly fights his client’s corner;
  • works tirelessly and meticulously to achieve the best outcome for defendants;
  • a keen strategist who identifies the issues quickly;
  • his work ethic and commitment are exceptional;
  • hugely understanding and sympathetic in dealing with all defendants who he represents;
  • he’s absolutely top drawer;
  • his skill in defending criminal cases, at all levels of seriousness, is unrivalled;
  • he takes a meticulous and refined approach to financial investigations;
  • gets results;
  • his recent elevation to Queens Counsel was thoroughly deserved;
  • an outstanding fraud lawyer;
  • a robust advocate;
  • a first class client manner;
  • I have never in my life seen a barrister work as hard as he did;
  • cool, calm and collected;
  • can handle complex issues with ease;
  • makes it all look easy;
  • instructed on cases involving voluminous evidence;
  • measured, careful analysis of the facts;
  • persuasive court advocacy style;
  • extremely intellectually sharp;
  • gallons of charm;
  • a highly sought after white collar barrister;
  • a phenomenal way of cutting through to the heart of a case;
  • presents his client’s case in a very robust and effortless way;
  • exceptionally good at fraud;
  • a very charming individual;
  • sources admire his diligence; and
  • he was out of this world.


A quarter of a century ago, a wise old man told an enthusiastic newly-qualified barrister the secret of success. “Any boxer,” he said, “can dazzle with footwork and fancy punches in the early rounds. But only the boxer who put in the roadwork in the months before will still be standing at the end of the fight.” He was right. No matter how skilful the barrister, there is no substitute for meticulous, comprehensive preparation in any and every case.

My family inspires me to do better. I love my work and I’ve always tried to challenge myself to improve what I can do for my clients, but nothing prepared me for how I would feel as a husband and a father. Making my family proud drives me to be the very best I can be at home and at court.

“Every one of my clients regards themselves as special. And rightly so; they are.”

When you’re backed against the wall, break it down. Or find a way around it. One of the things I enjoy most about my job is finding solutions for my clients. I want to understand what outcome they need to achieve and make it happen. It takes versatility, imagination and fearlessness, but I find enormous reward in seeing a happy client walk away with the very best outcome.

No two cases are ever the same. The people I meet, the cases in which I’m instructed, they each require a unique, tailored, individual approach. Every one of my clients regards themselves as special. And rightly so; they are.

It never hurts to smile. It’s a fact of life that barristers are involved where there is dispute and disagreement but not every exchange has to fuel that conflict. To a judge or jury, to court staff, to an opponent and especially to a client, courtesy, good humour and warmth can be both disarming and reassuring and a reminder that we are all only human.

Appointments and Memberships

  • Criminal Bar Association
  • Association of Regulatory and Disciplinary Lawyers
  • Proceeds of Crime Lawyers Association
  • Association of Military Court Advocates
  • Advisory Panel member for Inside Justice
  • Lead and Tutor Advocacy Trainer at Lincoln’s Inn
  • Mentor for the Lincoln’s Inn Pupillage Foundation Scheme
  • Mentor for The Social Mobility Foundation, a charitable organisation aimed at facilitating access to education and professions for young people from economically and socially deprived backgrounds.


Mark adopts and adheres to the provisions of his privacy notice which can be accessed here.


For further details of  Mark’s practice please click on the links to the left or contact a member of the clerking or client service team.

Bar Council Membership No: 33715

Registered Name: Mark Robert Harries

VAT Registration No: 691129919