Criminal Litigation
As Treasury Counsel since 2009 and Senior Treasury Counsel since 2015, Duncan has appeared in numerous complex and high profile homicide cases, including a number of high profile “cold cases”, together with homicides involving issues of contested medical causation, diminished responsibility and child-death. Duncan has particular expertise in cases of gross negligence manslaughter, deaths in the context of health and safety regulation, and deaths of persons in residential care or state detention.
Duncan has also appeared in numerous cases concerning allegations of terrorism, and relating to organised crime. In recent times, the former have included those planning attacks on the British Museum and Gay Pride, and latter has included the successful prosecution of the largest attempted importation of automatic weapons into the United Kingdom. Other cases in which he has also appeared as an advocate have involved allegations of rape, serious disorder, public nuisance, blackmail, prison escape, corruption, conspiracy to pervert the course of justice, and prosecutions under the Official Secrets Act.
Duncan also appears in cases of serious fraud and corruption, and has acted in both an advisory capacity and as an advocate for News UK, in the so called ‘hacking’ trials, for a UK FTSE company (GSK), and for senior executives in the international banking sector (the Staley FCA investigation and in relation to the Libor and Unaoil investigations).
Other cases in which he has also appeared as an advocate have involved allegations of rape, serious disorder, public nuisance, blackmail, prison escape, corruption, conspiracy to pervert the course of justice, and prosecutions under the Official Secrets Act. He has also appeared in the Supreme Court in relation to the propriety of prosecutions based on activity by paedophile hunters (Sutherland v HM Advocate [2021] AC 427) and the definition of sexual touching (AG’s Reference No.1 of 2020 [[2021] QB 441).
Homicide
Duncan has successfully acted in murder, manslaughter and attempted murder trials of all varieties, including cases of loss of control, self-defence, diminished responsibility, multi-handed ‘gang’ killings, juvenile defendants and cases with complex medical or other expert evidence. Recent cases have included:
Duncan also appeared in the Supreme Court when it reconsidered the liability of secondary parties in cases of murder (Jogee [2016] UKSC 8), and in the Court of Appeal both when the revised test was applied to six homicide cases (Johnson [2016] EWCA Crim 1613) and when the approach there identified was applied to a variety of homicide convictions (including Laura Mitchell [2018] EWCA Crim 2687; Johnson-Haynes [2019] EWCA Crim 1217). He also appeared when the Court of Appeal addressed the loss of control defence (Gurpinar [2015] EWCA Crim 178).
Terrorism
Duncan has an extensive experience of involvement in the whole gamut of counter-terrorism prosecutions, having in the course of his career appeared as Leading, Junior and Sole Counsel in high profile terrorism- related cases, including the “fertiliser bomber” case – Khyam which was then the largest joint operation of UK police forces, the security services and foreign law enforcement agencies. Recent cases have included:
Duncan has also acted as an adviser to the Government in relation to issues of disclosure in terrorism cases, and in relation to the drafting of guidance for the National Crime Agency. He appeared in the Supreme Court to address the meaning of “terrorism” in the Terrorism Act 2000 in the case of Mohammed Gul ([2013] UKSC 64), and in relation to the ‘port stop’ provisions of Schedule 7, Terrorism Act 2000 (Beghal [2015] UKSC 49).
Health & Safety and Regulation
Duncan has been instructed both in an advisory capacity and as an advocate in cases relating to breaches of Health and Safety and Environmental Protection legislation, both in criminal and inquest proceedings. In particular:
Fraud and Corporate Crime
Duncan has built up considerable experience in cases of serious and complex fraud and corruption, including cases involving the Serious Fraud Office, HMRC, the Financial Conduct Authority and the Department of Work and Pensions. He also has particular experience of Hi-Tech and computer-based fraud and other forms of “cybercrime” (see below), and in confiscation proceedings. Notable cases have included:
Duncan has also in an advisory role for:
Cybercrime
Duncan has been at the forefront of this developing area of criminal litigation. He acted from an early stage in an advisory capacity in Operation “Ore”, the international investigation of the incitement to supply indecent images of children. Other cases in this area have included Operation “Blossom”, a conspiracy to defraud the computer software industry with pirated software (the first large-scale prosecution by the National High-Tech Crime Unit) and the prosecution of fraud through the construction and distribution of malicious software.
Public & Administrative Law
Duncan is regularly instructed in relation to proceedings by way of judicial review, acting both in pre-action litigation and in the Administrative Court. Cases in which he has appeared have included:
Challenges by judicial review to prosecutorial decisions, and applications relating to SFO/Police search warrant applications.
Inquests & Public Inquiries
Duncan has been instructed to act for interested parties in several inquests before the Coroner’s Court. These have included appearing both at the inquest and subsequent prosecution relating to the Potters Bar derailment, and the inquest relating to the death of a soldier at military barracks. Duncan appeared in an advisory capacity in the 7/7 inquest. He has represented a number of the bereaved families at the Manchester Arena Bombing Inquiry before Sir John Saunders since 2020.