Addendum
Updated 22 October 2025
© Crown copyright 2025
This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3 or write to the Information Policy Team, The National Archives, Kew, London TW9 4DU, or email: psi@nationalarchives.gov.uk.
Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned.
This publication is available at https://www.gov.uk/government/publications/report-5-offensive-weapons-homicide-review-brent/addendum
Addendum following learning event held on 17 July 2025
The presence of regular and very high levels of nitrous oxide cannister inhalation featured as part of this review; not least as both FS and OA each and independently presented at hospitals with chest pains and high levels of anxiety in the weeks prior to the homicide. Consideration was given to potential effects of such nitrous oxide use as part of the review; however we were unable to make a clear and direct link between nitrous oxide and to the unexpected serious escalation in violence evidenced in this case.
During a learning event held in the London Borough of Brent on 17 July 2025 a medical practitioner raised insight into some emerging research indicating a link between nitrous oxide and its effects on depleting a person’s B12 resources, resulting in increased anxiety and psychosis. We are advised that B12 deficiency can be tested for and simply treated (by a course of injections or tablet medication) to reduce these symptoms.
As a result of this new insight, it is proposed to expand recommendation 2 (related to data capture of nitrous oxide presentations to hospital accident and emergency departments) to add:
“iv) to test for and capture any associated B12 deficiency in cases where individuals repeatedly present at A&E with chest pains and indicate particularly high use of nitrous oxide”.
“v) to work with Public Health to raise the profile of nitrous oxide and the health risks associated with a high levels of intake, with A&E departments and GP practices.”