The 2023 Nottingham attacks have produced one of the most complex examinations of expert witness evidence to reach a UK public inquiry in recent years. At its centre are three deaths, six victims and a chain of decisions involving mental-health professionals, police officers, prosecutors and emergency medical responders.
On 13 June 2023, Valdo Calocane fatally stabbed University of Nottingham students Barnaby Webber and Grace O’Malley-Kumar, both aged 19, before killing 65-year-old school caretaker Ian Coates. He subsequently stole Coates’ van and seriously injured three pedestrians: Wayne Birkett, Sharon Miller and Marcin Gawronski. Calocane, who had been diagnosed with paranoid schizophrenia in 2020, was subsequently sentenced to an indefinite hospital order after admitting three counts of manslaughter on the grounds of diminished responsibility and three counts of attempted murder.
The statutory Nottingham Inquiry, chaired by Her Honour Deborah Taylor, examined the acts and omissions preceding the attacks and the interaction between health, policing and criminal-justice agencies. Its evidence hearings ran from February to June 2026 and heard from 164 witnesses.
However, for expert witnesses, the case is particularly instructive because it demonstrates how expert opinion can inherently influence questions of causation, culpability, risk and preventability without determining those issues itself.
The Survivability Evidence
The most sobering expert evidence emerged during closing submissions in September 2026. Dr Claire Park, a witness and consultant in pre-hospital emergency medicine and intensive care, was asked to examine the medical records and witness statements relating to the three deceased victims. She considered, with an expert medical panel, whether earlier or different treatment might have altered the outcome.
Dr Park’s qualifications and experience are substantial. She is an MBE and holds MBChB, FRCA, FFICM, DipIMC and DipRTM qualifications. She is a consultant in pre-hospital emergency medicine with London’s Air Ambulance and in anaesthesia and critical care at King’s College Hospital. She also has extensive military medical experience and has worked on major-incident response and clinical governance.
The panel’s conclusion concerning Barnaby Webber was carefully expressed. His death was classified as “potentially preventable”, not as one that would probably have been prevented.
The evidence was that Webber received extensive treatment at the scene and that emergency responders worked together to provide compassionate and efficient care. Nevertheless, the panel considered that his care could have been improved. More aggressive volume resuscitation — replacing blood and fluid lost through his catastrophic injuries — might have allowed him to reach hospital sufficiently alive for immediate surgery to be considered.
Vitally, the experts did not say that survival was more likely than not. The chance was assessed as far below 50 per cent. Even with faster administration of blood products, “rapid and meticulous” additional interventions would have been required for him to survive to intensive care.
That distinction is important in legal analysis. An expert opinion that a death was potentially preventable is not equivalent to a finding that negligent treatment caused the death. The panel was addressing medical survivability and counterfactual treatment, leaving the legal assessment of responsibility to the Inquiry.
The conclusions regarding the other victims were unequivocal. Grace O’Malley-Kumar was already in cardiorespiratory distress when discovered. The panel considered her injuries not survivable, and concluded that even if she had been found at the same time as Webber, resuscitative treatment was unlikely to succeed. Ian Coates’ death was categorised as non-preventable because of the severity of his injuries; even an enhanced care team arriving immediately would not have been able to save him.
Psychiatric and Risk Expert Witnesses
The Inquiry also instructed experts to address the substantially different issue of violence risk associated with serious mental illness.
Professor Seena Fazel, Professor of Forensic Psychiatry at the University of Oxford, provided expert evidence concerning the relationship between mental illness, violence and risk assessment. His qualifications include medical training, membership of the Royal College of Psychiatrists and a doctorate in medicine. He has extensive academic and clinical experience in forensic psychiatry and has acted as an expert witness in homicide and other proceedings.
Professor Fazel’s evidence addressed structured violence-risk assessment. He considered that risk assessment should be undertaken when patients enter general adult psychiatric services and repeated when there is a significant escalation in risk, including arrest or other indications of changing circumstances. He also emphasised the value of standardised assessment tools and better communication of risk between agencies
Dr Ruth Tully, a Consultant Forensic Psychologist, provided complementary evidence. Her qualifications include a BSc(Hons), MSc, Doctor of Forensic Psychology, Chartered Psychologist status, Fellowship of the British Psychological Society and registration as a forensic psychologist with the Health and Care Professions Council.
Her expertise is particularly relevant to violence-risk assessment and management. She has worked in prison, healthcare and community settings and specialises in assessing risks associated with violent offending and other complex behaviours. The Inquiry heard her evidence specifically in relation to risk assessment and management.
Expert Witnesses Concerning Calocane’s Culpability
Professor Nigel Blackwood, Professor of Forensic Psychiatry at King’s College London, was instructed by the Crown Prosecution Service shortly after the attacks. He is a consultant forensic psychiatrist and leads the Forensic Research Group at King’s College London. His academic work includes the assessment and treatment of mentally disordered offenders and the relationship between mental disorder and offending.
Professor Blackwood assessed Calocane in the context of his criminal responsibility. His opinion was that Calocane’s retained responsibility was at the lower end of the spectrum. He and other psychiatrists recommended a restricted hospital order rather than a conventional custodial sentence. His evidence to the Inquiry also exposed an important limitation in the material supplied to an expert. He had not been shown some body-worn-camera footage and audio concerning Calocane’s earlier violent behaviour before preparing his report. The Inquiry subsequently heard that important information had emerged only later
Dr Richard Latham, a Consultant Forensic Psychiatrist, also gave evidence. He holds MBBS and MRCPsych qualifications and an LLM in mental-health law. He has extensive experience in complex psycho-legal matters and is an author of the Oxford Handbook of Forensic Psychiatry.
Dr Ross Mirvis, of Mersey Care NHS Foundation Trust, also appeared alongside Professor Blackwood and Dr Latham during the Inquiry’s examination of the psychiatric evidence.
Take Away For Expert Witnesses
The Nottingham Inquiry provides a powerful reminder that an expert’s opinion is only as reliable as the evidential foundation upon which it rests.
Professor Blackwood’s evidence demonstrates the danger of an expert being asked to reach conclusions without access to material subsequently shown to be relevant. By contrast, the survivability evidence demonstrates the importance of precise qualification: “potentially preventable” was not converted into “probably preventable”, and the panel distinguished sharply between the medical outcomes of the three victims.
For expert witnesses, the legal lesson is evident. Independence requires more than avoiding advocacy. It requires identifying the limits of the available evidence, stating assumptions, acknowledging uncertainty and resisting pressure to express a conclusion more strongly than the evidence permits.
In the Nottingham Inquiry, expert evidence, has therefore done more than illuminate medical and psychiatric questions. It has shown the essential forensic discipline of the expert witness: to assist the tribunal of fact with objective opinion, while leaving questions of legal responsibility and ultimate determination to the decision-maker.
By Edward Price
- The inquiry was held at Mary Ward House in London.
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