Gray’s Inn
South Eastern Circuit
Criminal Bar Association
The Kalisher Trust
Inside Justice Miscarriage of Justice organisation
The British Academy of Forensic Sciences
Member of the following charities – UK Sepsis Trust and Scoliosis Association
Siobhan Grey KC is a highly regarded King’s Counsel specialising in defending the most serious criminal law cases.
Siobhan was named “The Times Lawyer of the Week” in December 2024 for her role in overturning the 2004 murder conviction of Nardis Maynard in St Kitts and Nevis. Maynard was released from his life sentence after the murder conviction was quashed by the Privy Council.
Siobhan Grey KC is recognised as a leading King’s Counsel and described by Chambers and Partners and Legal 500 2025 Directories as:
‘Her preparation is incredibly detailed and very impressive and she is a tremendous advocate.’ Chambers and Partners (2025)
‘She is extremely dedicated and professional and has a good ability to handle complex legal issues as well as a compassionate and reassuring manner for clients.’ Chambers and Partners (2025)
‘She is very knowledgeable and proactive in preparing cases and excellent with clients. She leaves no stone unturned.’ Chambers and Partners (2025)
‘What sets Siobhan apart is her forensic approach and the detail she goes into when preparing.’ Chambers and Partners (2025)
‘Siobhan is a dedicated at KC at the zenith of the profession. She has excellent analytical skills. She is methodical and meticulous.’ Legal 500 (2025)
‘Siobhan is an adept communicator especially with vulnerable clients. She is a persuasive, skilled advocated. Siobhan is a real fighter and first choice counsel in murder cases.’ Legal 500 (2025)
The Directories also describe Siobhan as being:
‘A passionate smooth advocate with great communication skills’
‘Technically gifted and calm under pressure’
‘Openminded, methodical, meticulous and scientific in her approach to forensic evidence.’
‘She fights for her client and goes that extra mile’
‘Very hard working and persuasive’.
Siobhan Grey KC exclusively defends in high profile, complex and sensitive cases including murders, organised crime, fraud and sexual offences. She is highly accomplished in dealing with expert witnesses in the areas of pathology, psychiatry, DNA, blood spatter as well as telephone and cell site evidence. Siobhan is tenacious, committed and completely focused in her approach to her cases.
Siobhan is regularly instructed in murder and sexual offences due to her skills in cross examination and the way in which she examines in chief Defendants as well as having completely mastered the issues in relation to disclosure of unused material.
Siobhan Grey has a long history in defending in high profile, complex fraud cases. She has appeared in many of the leading fraud and business crime cases tried in London which include Insider Dealing, Pensions fraud, Conspiracy to defraud in relation to Alpha 6 detectors used by Governments and Military organisations across the globe as well as investments and Carousel frauds.
Siobhan Grey has been successful in the Court of Appeal in overturning two convictions recently. In 2021 she was instrumental in getting a conviction for murder overturned in the Court of Appeal. This was following fresh evidence having been obtained by investigative journalists based in Warsaw, Poland. The Defendant was subsequently unanimously acquitted of murder and manslaughter after a retrial at the Old Bailey. The case was the subject of a documentary, ‘ The Fourth Man’ by TVN 24 Poland.
Siobhan appeared before the Privy Council in 2024 where she led Richard Vardon. Siobhan was named “The Times Lawyer of the Week” in December 2024 for her role in overturning the 2004 murder conviction of Nardis Maynard in St Kitts and Nevis. Maynard was released from his life sentence after the murder conviction was quashed by the Privy Council.
Siobhan Grey KC has recently lectured and chaired seminars on ‘Neuroscience and the law’; Pathology and the Crime Scene; ‘Psychiatry and Homicide’. DNA and sexual offences’. She has also co-authored an article, ‘An Avenue to Miscarriage in Forensic Science, Medicine and Pathology’ in 2022.
Siobhan specialises in Homicide cases which regularly involves expert witnesses in the areas of pathology, psychiatry, blood spatter, toxicology and DNA evidence as well as telephone data, cell site and CCTV analysis.
Her murder cases are conducted both nationally as well as internationally. She has argued cases before the European Court of Human Rights in relation to the admissibility of hearsay evidence under the Criminal Justice Act 2003 in a gang-land murder case and has defended cases in the Caribbean as well as before the Privy Council of the United Kingdom.
Siobhan has a long history of defending in serious sexual offences involving historic sexual abuse; violent sexual assaults committed during the course of a homicide as well as internet sexual offending which engages multi-jurisdictional issues. Siobhan has completed the vulnerable witness training courses and is experienced at cross examining young and vulnerable witnesses. Furthermore, she understands the importance of disclosure issues in particular third-party disclosure in such cases and is always live to the question of s.41 of the Youth and Criminal Evidence Act 1999 as regards the admissibility of a complainant’s prior sexual history.
Siobhan has a long history of defending in fraud related offences including investment frauds, and MTIC frauds. She has defended in SFO prosecutions including a pension fraud worth over £50 million which was the biggest pension fraud since the Maxwell trial in the 1990s; a conspiracy to defraud involving £80 million whereby detector devices, ‘the Alpha 6’ were sold to Government and law enforcement agencies world-wide to detect explosives, drugs and weapons. She has defended company directors prosecuted under the Export Control Act 2002 for the alleged violation of UK export control regulations in relation to conventional arms and ammunition as well as dual use goods to Southeast Asia.
Siobhan has spoken at National events on Export Control and Dual Use items, which included the former head of the Secretariat for the Wassenaar Arrangement on export control of arms and ammunition.
In the context of Business crime, Siobhan Grey has detailed experience of dealing with Confiscation/POCA related matters and an extensive knowledge of the case-law in this area. The legal landscape has dramatically changed in relation to such proceedings over the years with the recognition and statutory prohibition involving a disproportionate interference with a convicted person’s property rights.
Cases include R v Pitcher, Southwalk Crown Court and arguments involving £52 million benefit figure as well as confiscation proceedings in the context of an Insider Dealing case R v Sanders, Southwark Crown Court.
Siobhan was instructed to defend in the News of the World’s Fake Sheikh ‘Red Mercury’ plot. The Prosecution alleged a plot to buy radioactive material. The Defendant was acquitted after a three-month trial at the Old Bailey concerning a conspiracy to fund terrorism and a conspiracy to possess an article for terrorist purposes.
R v C, Preston Crown Court, Oct – Nov 2023
Murder. The prosecution asserted that 4 men armed with weapons – metal poles and a hammer – broke into a house and murdered a vulnerable drug user. The case involved complex pathology issues concerning causation and a ruptured spleen.
R v S – Preston Crown Court, Feb – March 2023
Murder and Attempted Murder. This was a high-profile case involving the murder of a young woman in Blackburn who was shot and killed in a botched murder plot. The intended victim – a rival business-man – escaped unharmed. The prosecution’s case was that the Defendant was the mastermind behind the plan.
R v H Birmingham Crown Court, April 2023
The Defendant was charged with attempted murder having left home with a knife and then attacked a random stranger in the street. The case involved three psychiatrists and issues relating to paranoid schizophrenia.
R v P Manchester Crown Court, April – May 2023
The Defendant was charged with the high-profile murder of a Manchester Met University student. The prosecution alleged that in response to a light hearted comment the Defendant produced a flick knife which he proceeded to use causing 8 stab wounds. The killing was caught on CCTV.
R v S, Bolton Crown Court, Jan- Feb 2023
This case involved a criminal gang planning the false imprisonment, torture and killing of a rival drug dealer who in the days leading up to his death was tracked and monitored on a daily basis with frequent visits to his home address in order to carefully plot the criminal enterprise. The case involved important issues on DNA evidence and secondary transfer.
R v Sanders, Southwark Crown Court, 2012
A prosecution brought by the Financial Services Authority in conjunction with an investigation by the US Department of Justice (DoJ) and the US Securities and Exchange Commission (SEC) together with the Federal Bureau of Investigations in the USA which concerned a partner at Deloitte’s M and A division in San Francisco passing information about mergers and acquisitions in US securities listed on the NYSE and NASDAQ exchanges. The prosecution’s case was that the Defendants, who ran a specialist contract for difference brokerage, traded on the information from the partner at Deloitte and encouraged clients to trade on it too which resulted in profits of over £10 million.
R v Pitcher, Southwark Crown Court, 2012
This case was labelled the biggest pensions fraud since the Robert Maxwell case in the 1990s. The Defendant was an independent pension trustee administering a large number of occupational pension schemes related to companies which had become insolvent or had gone into liquidation. The Defendant was alleged to have moved £52 million from secure gilt-based investments from the UK to Swiss bank accounts held in the name of companies registered in the British Virgin Islands.
R v T, Central Criminal Court, 2014
Conspiracy to defraud in relation to devices termed Alpha 6 which were sold internationally to Governments and Military organisations as well as in the search for Madelaine McCann on the basis that they could detect explosives, drugs or even missing people. They were said to excite neutrons and ions within the device to make the antenna work.
R v H, Bolton Crown Court, 2016
An international Mortgage Fraud relating to the purchasing of properties in the Cayman Islands and the United Kingdom
R v P, Cardiff Crown Court, 2019
The Prosecution case focused on the Defrauding of the European Union and Welsh Government of £5.19m by claiming EU and Welsh government funds to develop a fishmeal alternative. The frauds took place over a prolonged five- year period. Part of the venture had been aimed at creating an innovative feed for fish farms which could limit the impact on the oceans by using his specially harvested and farmed ragworms instead of traditional fishmeal which itself was made from wild caught fish.
Siobhan Grey KC has a vast amount of experience in cross-examining witnesses in rape and other sexual offences.
R v I. Preston CC, 2023
The Defendant was charged with seven counts of rape and sexual assaults on a woman known to the Defendant from his school days whom the prosecution alleged had bullied her. The case included complex DNA evidence regarding the Defendant’s DNA found on the complainant’s breast and issues regarding secondary transfer regarding the DNA as well as many physical injuries to the complainant’s face and neck which the Crown alleged was as a result of attempted strangulation.
R v M Carlisle Crown Court ( June 2023)
Allegations of sexual touching involving young children. Defendant acquitted of all charges.
R v R – Chichester Crown Court ( January 2023)
Student accused of rape. Defendant acquitted of the Rape.
R v K – Birmingham Crown Court (November 2022)
The Defendant was a night club owner charged with multiple allegations of rape involving two female students. Defendant acquitted of all charges.
R v JR ( Lewes Crown Court) (June 2022)
Defended a police community support officer charged with multiple rapes. Defendant acquitted of all charges.
Presented a zoom seminar on Diminished Responsibility in Homicide cases. May 2020.
Presented a seminar on Expert witnesses in Homicide cases – a look at Pathology, DNA, Blood Spatter and Neuro-Psychiatry. July 2019.
Presented a seminar on Disclosure in the Criminal Courts, Gray’s Inn, Oct. 2017.
Presented a seminar on the Export Control Act 2002 and the export of Dual Use Goods, July 2017.
Chaired a seminar on Freedom of Expression and the Internet and criminal offences Florence University, July 2013.
Devised and presented a Symposium at the European Parliament’s Grand Chamber on the Impact of the Internet and Social Media Platforms. Brussels, June 2012.
Siobhan Grey KC and Richard Vardon were successful in the Privy Council in overturning a murder conviction from 2004.
The prosecution will not be seeking a retrial, and the appellant has been released from prison after serving 20 years of a life sentence. They worked together with Talibah Byron, Attorney of Byron Law in St Kitts, The Death Penalty Project and Saul Lehrfreund MBE & Killian Moran Simons Muirhead Burton LLP. Details of the case can be found on The Privy Council.
Murder
Siobhan specialises in Homicide cases which regularly involves expert witnesses in the areas of pathology, psychiatry, blood spatter, toxicology and DNA evidence as well as telephone data, cell site and CCTV analysis.
Her murder cases are conducted both nationally as well as internationally. She has argued cases before the European Court of Human Rights in relation to the admissibility of hearsay evidence under the Criminal Justice Act 2003 in a gang-land murder case and has defended cases in the Caribbean as well as before the Privy Council of the United Kingdom.
R v S – Preston Crown Court (Feb/March 2023) Murder trial lasting 5 weeks appearing for the first Defendant.
This was a high profile case involving the murder of a young woman in Blackburn who was shot and killed in a botched murder plot with the intended victim escaping unharmed. The prosecution’s case was that the defendant was the mastermind behind the plan.
R v H – Birmingham Crown Court ( April 2023) The Defendant was charged with attempted murder having left home with a knife and attacked a random stranger in the street. The case involved three psychiatrists and issues relating to paranoid schizophrenia.
R v P – Manchester Crown Court ( May 2023). Murder trial appearing for the Defence.
The Defendant was charged with the high-profile murder of a Manchester Met University student. The prosecution alleged that in response to a light-hearted comment, the Defendant produced a flick-knife which he proceeded to use causing 8 stab wounds – the killing was caught on CCTV.
R v RS, Bolton Crown Court (January 2023) A 5 week multi-handed murder trial which involved a conspiracy to rob and murder. The case involved complex DNA evidence regarding secondary transfer and the sufficiency of such material as well as a detailed analysis of telephone and cell site data resulting in cross examination of experts in these fields.
R v S, Leicester Crown Court (July 2022). A homicide case which involved decapitation of the deceased’s head with a long history of domestic violence perpetrated by the deceased against the Defendant. The case required the extraction of electronic data from a telephone depicting the history of abuse and which resulted in the case being reduced from murder to manslaughter.
R v Rahman Central Criminal Court, Old Bailey (February 2022) A 6 week murder trial which involved extensive cross examination and a detailed analysis of the CCTV evidence which prominently featured in the case.
R v Pachecka: Central Criminal Court, Old Bailey (November 2021) An 8 week re-trial for Murder after the conviction was overturned in the Court of Appeal. The case involved complex medical evidence regarding PATHOLOGY with multiple experts to examine. Four pathologists gave evidence as well as multiple scientific forensic experts which undermined the whole JOINT ENTERPRISE argument advanced by the prosecution. The case has been the subject of an international documentary made by investigative journalists based in Poland.
R v Thompson: Newport CC (March 2021) A 10 week trial. The Defendant, along with others, was charged with the murder of a 17 year old boy. The case concerned a drugs turf war. The case concerned important principles about withdrawing from a JOINT ENTERPRISE.
R v Pachecka and Others Court of Appeal (December 2020) Siobhan Grey KC led the legal arguments in the Court of Appeal, Criminal Division. The appeal involved investigative journalists based in Warsaw who unearthed fresh evidence.
R v Lall. Inner London Crown Court. (November 2020) The Defendant was charged with murder. The case involved complex PSYCHIATRIC evidence concerning paranoid schizophrenia, non-compliance with medication and impairment of self-control in the context of mental illness. The Defendant was given a Hospital Order. The Prosecution sought to appeal the Hospital Order by way of an Attorney General’s Reference on the grounds that the sentence was too lenient. The Defence was successful in resisting the AG’s Reference and the Hospital Order was upheld.
R v H: Cardiff Crown Court. (June 2019). A 6-week trial. Represented a boy aged 17 who suffered with a severe stammer and had been diagnosed with ADHD and a Depressive Disorder. He was charged with murder and the trial involved five co-accused in relation to the torture and stabbing of a young man.
R v P: Central Criminal Court, Old Bailey. (November 2018). Represented a man charged with the murder of his employer at her home address. The issues focused on the nature of the Defendant’s medication and its impact on his brain. This case involved extensive investigations into pharmacology and heptology.
R v O: Swansea Crown Court. (October 2018). Represented a woman charged with murdering a pensioner in his own home. The case involved three Defendants and focused on the unreliability of non-statistical DNA evidence.
R v H: Inner London Crown Court. (May 2018). The Defendant was charged with Manslaughter having sold slimming tablets over the internet resulting in death of a vulnerable young woman.
R v F: Sheffield Crown Court. (October 2017) A 4-week trial. Represented a man charged with the torture and murder of a drug user. The case involved three Defendants and focused on the unreliability of mobile phone and social media evidence in a case where the Defendant was running alibi.
R v Goodall: Sheffield Crown Court (October 2016) Represented a man charged with murder. The case concerned causation issues requiring the cross-examination of numerous expert witnesses in the areas of pathology; orthopaedic medicine; cardiology and heptology.
R v Seton: European Court of Human Rights (October 2015) Gang land shooting. The issue turned on the admissibility of Hearsay evidence in a murder trial. The case is reported in Criminal Law Review Commentary 2016.
Sexual offences
Siobhan has a long history of defending in serious sexual offences involving historic sexual abuse; violent sexual assaults committed during the course of a homicide as well as internet sexual offending which engages multi-jurisdictional issues. Siobhan has completed the vulnerable witness training courses and is experienced at cross examining young and vulnerable witnesses. Furthermore, she understands the importance of disclosure issues in particular third-party disclosure in such cases and is always live to the question of s.41 of the Youth and Criminal Evidence Act 1999 as regards the admissibility of a complainant’s prior sexual history.
R v M: Carlisle Crown Court (June 2023) Successfully defended in a case alleging multiple allegations of sexual offending involving child complainants, aged 10, Ms Grey KC was instructed by the senior partner, Neal Gozzett at Monan Gozzett solicitors.
R v R – Chichester Crown Court ( January 2023) Student accused of rape,
R v K – Birmingham Crown Court (November 2022) The Defendant was a night club owner charged with multiple allegations of rape involving two female students.
R v JR – Lewes Crown Court (June 2022) Defended a police community support officer charged with multiple rapes.
R v N: Maidstone Crown Court (March 2022) The case involved historic allegations of rape and sexual assault. The case involved cross examination of the complainant with detailed disclosure of third-party material from outside the jurisdiction.
R v W: Portsmouth Crown Court (January 2022) The case involved historic allegations of sexual assault and the Crown asserted that one allegation was caught on the camera of a mobile phone.
R v B: Winchester Crown Court (August 2021) The case involved multiple historic sexual offences and again a detailed knowledge of the disclosure of unused material was required.
R v S: Lewes Crown Court (July 2019) Represented a priest charged with multiple historic sexual offences. The case involved legal issues such as severance; third party disclosure and ultimately psychiatric evidence concerning fitness to plead and stand trial.
R v W: Croydon Crown Court. (May 2019) Represented a man charged with 18 counts of sexual assault alleged to have been committed over skype. There was extensive legal argument on the admissibility of hearsay evidence, including anonymous hearsay, found on the Defendant’s telephone and computer.
R v G: Guildford Crown Court (August 2018) Represented a man on multiple historic allegations of child cruelty dating back to the 1980s and 1990s. The case involved extensive disclosure issues as regards third party material in relation to all complainants.
R v HB: Guildford Crown Court (February 2018) Represented a man charged with stalking who applied a tracker to his ex-wife’s car. The issue turned on the construction of the words in the Protection from Harassment Act 1997.
R v P. Croydon Magistrates’ Court. (October 2017) Represented a man charged with rape and sexual assault. The case focused on seeking and obtaining disclosure of the defendant’s telephone which highlighted the extensive messages sent to the Defendant by the complainant.
R v R: Oxford Crown Court (September 2016) Represented a deaf man with learning difficulties charged with rape. The case involved numerous intermediaries during the trial process and a careful understanding of how to present the Defendant’s evidence in chief before the jury in line with the Advocates’ tool kit for vulnerable witnesses.
Business Crime
Siobhan has a long history of defending in fraud related offences including investment frauds, and MTIC frauds. She has defended in SFO prosecutions including a pension fraud worth over £50 million which was the biggest pension fraud since the Maxwell trial in the 1990s; a conspiracy to defraud involving £80 million whereby detector devices, ‘the Alpha 6’ were sold to Government and law enforcement agencies world-wide to detect explosives, drugs and weapons. She has defended company directors prosecuted under the Export Control Act 2002 for the alleged violation of UK export control regulations in relation to conventional arms and ammunition as well as dual use goods to Southeast Asia. Siobhan has spoken at National events on Export Control and Dual Use items, which included the former head of the Secretariat for the Wassenaar Arrangement on export control of arms and ammunition.
In the context of Business crime, Siobhan Grey has detailed experience of dealing with Confiscation/POCA related matters and an extensive knowledge of the case-law in this area. The legal landscape has dramatically changed in relation to such proceedings over the years with the recognition and statutory prohibition involving a disproportionate interference with a convicted person’s property rights. Cases include R v Pitcher, Southwalk Crown Court and arguments involving £52 million benefit figure as well as confiscation proceedings in the context of an Insider Dealing case R v Sanders, Southwark Crown Court.
R v P: Cardiff Crown Court. Acted for an Accountant charged with Defrauding the European Union and the Welsh Government of £5.19m in grants.
R v M: Southampton Crown Court. Acted for an Accountant on an indictment involving eight defendants charged with Conspiracy to Defraud by using the Construction Industry Scheme to defraud HMRC of over £1million of tax owed by subcontractors in demolition projects.
R v P: Central Criminal Court: Represented a company director on 22 counts of Fraud and exporting dual purpose goods (commercial and military items) to China without a licence. The case involved novel and complex legal argument concerning the EC Regulation 428/2009 in relation to Export Control and whether it lacked legal certainty in the context of the classification of Microwave Monolithic Integrated Circuits. Three expert witnesses in the fields of electrical engineering and export control were engaged in the case.
R v A: Bolton Crown Court: Defended one of two defendants charged on an indictment with 27 counts of Fraud and Money Laundering involving millions of pounds regarding property in the Cayman Islands.
R v S: Manchester Crown Court. Defended the wife of the principal defendant in a £200 million money laundering regarding a licensed money service business specialising in remitting money to Pakistan.
Terrorism
Siobhan was instructed to defend in the News of the World’s Fake Sheikh ‘Red Mercury’ plot. The Prosecution alleged a plot to buy radioactive material. The Defendant was acquitted after a three-month trial at the Old Bailey concerning a conspiracy to fund terrorism and a conspiracy to possess an article for terrorist purposes.
Siobhan specialises in Homicide cases which regularly involves expert witnesses in the areas of pathology, psychiatry, blood spatter, toxicology and DNA evidence as well as telephone data, cell site and CCTV analysis.
Her murder cases are conducted both nationally as well as internationally. She has argued cases before the European Court of Human Rights in relation to the admissibility of hearsay evidence under the Criminal Justice Act 2003 in a gang-land murder case and has defended cases in the Caribbean as well as before the Privy Council of the United Kingdom.
Siobhan has a long history of defending in serious sexual offences involving historic sexual abuse; violent sexual assaults committed during the course of a homicide as well as internet sexual offending which engages multi-jurisdictional issues. Siobhan has completed the vulnerable witness training courses and is experienced at cross examining young and vulnerable witnesses. Furthermore, she understands the importance of disclosure issues in particular third-party disclosure in such cases and is always live to the question of s.41 of the Youth and Criminal Evidence Act 1999 as regards the admissibility of a complainant’s prior sexual history.
Siobhan has a long history of defending in fraud related offences including investment frauds, and MTIC frauds. She has defended in SFO prosecutions including a pension fraud worth over £50 million which was the biggest pension fraud since the Maxwell trial in the 1990s; a conspiracy to defraud involving £80 million whereby detector devices, ‘the Alpha 6’ were sold to Government and law enforcement agencies world-wide to detect explosives, drugs and weapons. She has defended company directors prosecuted under the Export Control Act 2002 for the alleged violation of UK export control regulations in relation to conventional arms and ammunition as well as dual use goods to Southeast Asia. Siobhan has spoken at National events on Export Control and Dual Use items, which included the former head of the Secretariat for the Wassenaar Arrangement on export control of arms and ammunition.
In the context of Business crime, Siobhan Grey has detailed experience of dealing with Confiscation/POCA related matters and an extensive knowledge of the case-law in this area. The legal landscape has dramatically changed in relation to such proceedings over the years with the recognition and statutory prohibition involving a disproportionate interference with a convicted person’s property rights. Cases include R v Pitcher, Southwalk Crown Court and arguments involving £52 million benefit figure as well as confiscation proceedings in the context of an Insider Dealing case R v Sanders, Southwark Crown Court.
Siobhan was instructed to defend in the News of the World’s Fake Sheikh ‘Red Mercury’ plot. The Prosecution alleged a plot to buy radioactive material. The Defendant was acquitted after a three-month trial at the Old Bailey concerning a conspiracy to fund terrorism and a conspiracy to possess an article for terrorist purposes.
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