The Challenge of Proving Prevention: The Inquest of Linda O’Brien v Assistant Coroner

The High Court rejected an application for judicial review in the case of O’Brien v HM Assistant Coroner for Sefton, Knowsley and St Helens which limited the scope of the inquest into the death of Linda O’Brien. Linda’s family contended that had her ex-partner, who was subject to a restraining order but present at her flat on the day of her death, been arrested one month prior, her death might have been prevented. The judicial review was of a decision taken by Mr Graham Jackson, HM Assistant Coroner, on 15 March 2023 that there was no coronial causation established linking previous conduct by officers of the Merseyside Police and the events resulting in Linda’s death.

Background and scope

Linda O’Brien died on 9 May 2020 after falling from a fourth-floor window at the age of 49. Her ex-partner, Alan McMahon, was the only other person present in her flat at the time. Mr McMahon was subject to a five-year restraining order due to a history of previous violence towards Linda.

One month prior to her death, on 7 April 2020, four police officers attended Linda’s flat, finding Mr McMahon present and intoxicated. The officers were unaware of his restraining order and maintained that they had checked relevant police databases which showed no reference to the restraining order. They maintained that if they had been aware of the order, they would have arrested him for breaching it.

On 9 May 2020, Mr McMahon called the emergency services when Linda fell from the window. The police attended and arrested Mr McMahon on suspicion of murder. A postmortem examination of Linda’s body found she was significantly intoxicated, and additional injuries were present which suggested possible prior assault.

On 19June 2020, Mr McMahon was sentenced to 20 months’ imprisonment for breach of restraining order and theft. The accusation of murder was not proceeded with.

On 7 June 2022, a pre-inquest review hearing was held, and a request for a second pre-inquest review hearing was made. On 15 March 2023, after considering submissions by the Claimant and Merseyside Police, the Coroner made the decision that there was no coronial causation between the events involving police officers on 7 April 2020 and events on 9 May 2020. He decided the inquest should focus solely on the events of the night Linda died, excluding the failure to arrest Mr McMahon on 7 April. Consequently, the inquest’s scope was limited, and the police’s prior failures were considered only as background information.

The Claimant was given permission for judicial review of this decision on the grounds that the Coroner had erred in “prematurely and irrationally deciding that there [was] no causative connection between the acts and omissions of Merseyside Police and the death of Linda O’Brien and thereby unlawfully limiting the scope of the investigation.” [28] They argued that earlier police action could have prevented the death and that the police’s failure to act should have been fully investigated.

Outcome

The High Court, in its judgment handed down in February 2025, dismissed the application for judicial review.

The court acknowledged that had Mr McMahon been arrested earlier, he might have been in custody on 9 May 2020, and it was therefore “possible that Linda’s death would not have occurred.” [42] However, this scenario was deemed “entirely speculative” [42] and unsupported by evidence. It was held that a substantive causative link could not be established on the balance of probabilities, and there was insufficient evidence to demonstrate that Mr McMahon would have been in custody on the date of Linda’s death. It could not be proved that, on balance, “anything done or not done by police officers on 7 April or subsequently more than minimally, negligibly or trivially contributed to Linda’s death.” [47]. Therefore, the Coroner was entitled to rule the police conduct out of the scope of the inquest, and the decision to limit the scope of the inquest was upheld.

The Court also rejected the claim that the inquest required a jury under section 7 of the Coroners and Justice Act 2009 due to potential police failings. As no probable causative link could be shown, the threshold for requiring a jury was not met.

Commentary

This case underscores a broader and enduring tension within coronial law: the need to balance the public interest in accountability with the evidentiary thresholds that define and constrain a coroner’s jurisdiction. Bereaved families may look to the inquest process for a fuller understanding of the circumstances surrounding a death, particularly in cases involving domestic abuse, institutional failings, or missed safeguarding interventions. But the law remains tightly bound to legal causation. The critical legal distinction between what is possible and what is merely speculative remains at the heart of the decision in this case.

While the police’s failure to arrest Mr McMahon on 7 April 2020 was a significant oversight, the court’s decision reflects the difficulty in establishing a direct link between this failure and Linda’s subsequent death. The ruling highlights the legal principle that inquests must be based on evidence that can establish causation on the balance of probabilities, rather than on speculative scenarios. As a result, even serious institutional shortcomings may fall outside an inquest’s formal remit if they cannot be shown to have contributed, more than minimally or trivially, to the death.

Lucy Evanson is part of the Inquests Team at Parklane Plowden. Lucy’s profile can be accessed here.