Mary Prior KC > The 36 Group > London, England > Lawyer Profile

The 36 Group
Gray's Inn, 4 Field Court

Work Department

36 Crime


In the past two years Mary has secured the acquittal of the youngest person in the United Kingdom to be accused of terrorism. She represented the stepmother of Arthur Labinjo Hughes at her trial for murder and cruelty and successfully argued at the Court of Appeal that her sentence was not unduly lenient. She secured the acquittal of the alleged leader of a significant organised crime group who was said to run the sale and supply of drugs and firearms in the Coventry area of the Midlands by violence and threats. She secured the conviction on retrial of Emma Magson and the conviction of John Jefferies who killed two young men in revenge for damaging his car. She is currently instructed to prosecute two horrific murders of 10 month old babies in the Derbyshire area.

Mary Prior KC has a reputation for being a powerful, persuasive advocate who commands the respect of the court room and gets results. She has especial expertise with the vulnerable including people on the autistic spectrum, with ADHD, learning difficulties, addictions, sex workers, those in the “looked-after” system. She is regularly instructed to prosecute and defend cases where the key witnesses are vulnerable (children/special needs). Mary takes highly complex factual and legal cases and presents them in a simple manner to ensure everyone understands the issues. She takes great care to ensure that all relevant material is considered and utilised. When prosecuting, she gains the trust of the families of the deceased and works well as part of a team of officers and lawyers. When defending she regularly visits her clients, gains their trust and determines a focussed trial strategy. Mary is fearless when cross-examining those who require a robust approach. She ensures that the best points in a case are not lost by focus on irrelevancies. She prosecutes and defends in equal measure in the best traditions of the independent Bar. She provides early and thorough written advice and strategy as to the best approach. She is often commended by Judges for her handling of cases and of witnesses.

She is often instructed in murders of children involving complex medical evidence, homicides by groups of young people, homicides with a history of domestic violence, all homicides, organised crime groups using firearms and violence to distribute drugs on a massive scale. She is instructed in multi-defendant and complainant historic sexual offences which involve the control of people, slavery and sexual exploitation.

She was called to the Bar in 1990 and has over 30 years experience as a criminal barrister.






Work undertaken:

Organised crime groups
Homicide – death of children
Homicide – history of domestic violence
Homicide – youths
Rape and serious sexual offences and historical sexual offences
Large scale child sexual exploitation
Institutionalised child sexual abuse
Large scale conspiracies to import drugs
Work which crosses family and criminal law – arson, child abduction, homicide, cruelty.


Called 1990; Gray’s Inn; Silk: 2017.


Quarterly RASSO newsletter Midland Circuit.
Academic papers on memory and intoxication, interview techniques for inebriated witnesses.
Chapter for special measures in Human Trafficking and Modern Slavery
Flowe, H., Carline, A., Takarangi, M., Humphries, J., French, S., & Prior, M. (2015). Sexual violence and complainant intoxication. Criminal Justice & Law Weekly, 179 (34).
Contributor to Alcohol and Remembering Rape – New Evidence for Practice Palgrave McMillan.



Appointed QC 2017
Bencher at Gray’s Inn
Vice Chair of Education – outreach – Gray’s Inn
Head of Corporate Social Responsibility, the 36 Group
CBA QC elected representative
Head of RASSO Training Midland Circuit
Head of Social Mobility Midland Circuit
Vulnerable Witness trainer/facilitator ICCA
Gray’s Inn advocacy and ethics trainer
Women in Criminal Law – Joint Chair Midlands Branch
Deputy Head of Criminal Team – the 36 Group
Trainer for Leicestershire Police disclosure champions
Co-Chair Leicestershire Schools Courts Competition


Midland Circuit
South Eastern Circuit
Criminal Bar Association
Gray’s Inn
Visiting professional fellow Aston University.
Editorial Board The Contemporary Law Forum -India
Women in Criminal Law
Patron of Bristol University Criminal Justice Society
Patron of Northumbria Bar Society
Trustee of Bringing (Dis) Ability to the Bar
Champion of Neurodiversity in Law
Patron of the Non-Russell Group of Lawyers

Other posts and committees:

On the working committee for the questioning of inebriated witnesses/complainants
Legal advisor to Healed with Compassion
Co-organiser of the Leicester Schools Mock Trials Competition
Bar Council Social Mobility Advocate 2019
Publishes Quarterly RASSO newsletter Midland Circuit
Publishes academic papers on memory and intoxication, interview techniques for inebriated witnesses
Editorial Board The Contemporary Law Forum -India
Women in Criminal Law
Patron of Bristol University Criminal Justice Society
Patron of Northumbria Bar Society
Trustee of Bringing (Dis) Ability to the Bar
Champion of Neurodiversity in Law


Anglia Ruskin University (LLB (Hons)); Inns of Court School of Law (BVC (Very Competent)).

Lawyer Rankings

Regional Bar > Midland Circuit > Crime (general and fraud)

(Leading Silks)Ranked: Tier 1

Mary Prior KCThe 36 Group ‘Mary is a powerful and compelling advocate whose emotional intelligence and empathy give her a real tactical advantage, whether she prosecutes or defends. She is 100% committed to her cases, and her work is outstanding.’  

The 36 Group is a ‘good all-round chambers’ with a set of ‘good quality advocates’ and strong presence in the Midlands circuit. Mary Prior KC is ‘particularly good at questioning vulnerable witnesses’ and recently handled a murder case involving complex medical evidence. Sarah Gaunt handled a case of a widescale and country-wide sophisticated ATM theft conspiracy. Nadeem Holland prosecuted and convicted a thirteen-defendant drug conspiracy case, in which all defendants were convicted. Samuel Skinner is an ‘ambitious and astute lawyer with excellent judgement’ and prosecuted around 109 defendants in dozens of linked trials of conspiracy to supply drugs. Mary Loram KC and William Harbage KC, as were, have been appointed circuit judges, based in Chelmsford and Nottingham respectively.