NEWS & EVENTS

R (O'Brien) v HM Assistant Coroner for Sefton: Has Anything Changed?

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Facts

Linda O'Brien fell to her death from the window of her flat on 9th May 2020, a flat in which Mr McMahon was present at the time and who phoned the police shortly thereafter. They had been in an intimate relationship, there was a history of domestic abuse, and the post-mortem indicated that she had injuries consistent with a recent prior assault. Linda O'Brien had previously indicated that she would use a drainpipe, near the window from which she fell, as an escape route from Mr McMahon.

Officers had attended her flat just one month prior, on 7th April 2020, following a neighbour reporting an ongoing domestic incident in which screaming was heard. Mr McMahon was present, in breach of a restraining order, but Linda O'Brien denied anything had occurred. The officers did not know about the restraining order (notwithstanding checks on police systems), and so did not arrest Mr McMahon; had they known, they said that they would have arrested him. On 15th April 2020, an officer investigating an earlier offence identified the breach and began to progress it.

Following her fall on 9th May 2020, Mr McMahon was arrested on suspicion of murder (and released on bail, although this offence was ultimately not pursued), and later arrested, convicted and imprisoned for multiple restraining order breaches.

The coroner ruled that the inquest would be heard without a jury as a non-Article 2 inquest. He temporally limited the scope to events on the 8th and 9th May 2020, deciding that events on and after 7th April 2020 did not "require extensive investigation" and would be for "background and information purposes". Unfortunately, there was little explanation/reasoning for his decision and/or why he considered there to be no coronial causation (explaining only in pre-action correspondence to the judicial review ['JR'] proceedings that anticipating the likely outcome following arrest was too speculative). It was his decision on scope (and ultimately his view on causation) that formed the basis of the appeal (the High Court having refused permission on other grounds), the appeal being against the High Court's dismissal of the Claimant's claim for JR.

Decision

Broadly, the Appellant's case was that the inquest should investigate whether anything could or should have been done on or after 7th April 2020 which would have meant that Mr McMahon was not in Linda O'Brien's flat on the night she died. The Court of Appeal decided that this involved a consideration of whether, if the officers had known of the restraining order, he would have been arrested and charged, with the result that he would have been either on remand awaiting trial or serving a sentence for breach on the night she died.

The Court of Appeal was critical of the High Court's approach, in that the Judge had erred in law in making his own findings of fact as to what the evidence showed in respect of causation, rather than addressing whether the coroner had prematurely and irrationally decided that there was no causative connection between the actions of the police and the death. The Court therefore considered that it should review the decision of the coroner for itself to determine whether the challenge was made out.

In summary, in setting out the factors that the coroner ought to have considered, Lord Justice Edis provided a fairly firm indication as to what probably would have occurred had Mr McMahon been arrested on 7th April 2020; essentially, on the facts of this case, it was likely that he would have in custody on the night Linda O'Brien fell 31 days later. Certainly, the Court considered that it was wrong to find that such an outcome could not have been known (and to therefore rule it out of scope), and that making such a decision without considering Mr McMahon's criminal history was premature and, in this context, irrational and flawed on that basis alone. The Court of Appeal was critical that the coroner had not only ruled out the events of 7th April 2020 from the investigation, but, in JR pre-action correspondence, also appeared to express a concluded view on it not being possible to know whether Mr McMahon played a causative role in her death.

Interestingly, the Court found that the coroner (and, implicitly, the High Court) should have had regard to the Sentencing Guidelines and Code for Crown Prosecutors, in addition to Mr McMahon's antecedents, when considering the likely outcome of arrest. The Court went as far as setting out the Guidelines, identify where it considered the breach would have sat therein, the starting point and sentencing range would have been (12 weeks' imprisonment, with a range extending up to a year), the aggravating factors, probable lack of suspension, and, virtually, what the likely sentence would have been. The Court went so far as to express a clear view that there was no reason to suppose that, had he been arrested, he would not have been charged and produced the following day. It was held that, if he had pleaded guilty, it was not just probable, but "highly likely" that he would have been in prison on the day Linda O'Brien died. If he had pleaded not guilty, the clear inference from the judgment was that the Court considered it likely that he would not have been granted bail.

The Court of Appeal acknowledged that other outcomes/decisions were possible, but held that consideration of the possibilities did not prevent an assessment of what probably would have happened, and the assessment should proceed not on the basis as if the criminal justice process were "a random affair whose outcomes could not be predicted" but that decision-makers would have acted rationally on the evidence available. The Court of Appeal said that there was no indication that the coroner knew anything about sentencing practice, charging or bail decisions and, if a court lacked expertise, it was open to the court to receive expert evidence to fill any knowledge gap. Whilst the evidence to be obtained is a matter for the coroner, with a wide ambit of discretion, the Court considered that the High Court was wrong to say that it was not possible to obtain reliable evidence to enable the coroner to be satisfied as to what would have occurred following arrest, because the discretion was here exercised on a flawed assessment of causation.

The Court found that the coroner's premature decision on causation also effectively infected his decisions on Article 2 engagement and jury, which would need to be reconsidered.

Costs

The Coroner

The Court of Appeal highlighted from earlier authorities that "neutrality is a matter of substance, not form". It found that the claims of neutrality were not made out by the content of the submissions made, which contained "a robust defence" of the decision of the coroner, and passages in his skeleton argument averring neutrality did not detract from that. In so doing, the Court did not accept that the coroner's pre-action correspondence was irrelevant to this issue, nor that he was required to explain and justify his decision therein.

The Interested Party

The Chief Constable submitted that costs ought to be borne by the coroner, the defect being the initial decision which was attributable to him, and that it was reasonable for the Chief Constable to make submissions as it had a proper and distinct interest in the issue before the Court. The starting point was discretion. The Court underlined that the interests of the Respondent and the Interested Party were different but aligned to the same objective (to persuade the Court as to the correctness of the decision under challenge), that the principle to be applied is the general rule and that the Interested Party would no doubt have sought its costs had the appeal been dismissed.

Two reasons were cited in awarding costs:

The coroner's pre-action letter of response adopted the submissions made by the Chief Constable, so they were the origin of the legal error which ultimately led to the appeal being allowed.
The Interested Party had "the institutional competence" to assist the coroner in what would have happened had Mr McMahon been arrested; his previous convictions should have been supplied.

Accordingly, the Court ordered both the Respondent and Interested Party to pay the Appellant's reasonable costs of the JR proceedings and appeal, bearing 50% each, but with joint and several liability.

Take-aways

The first point is that O'Brien does not establish any new point of law, and is a case largely constrained to its facts.
It does, however, highlight that potentially causative matters should not be ruled out of scope, and therefore out of the investigation, at an early stage. That, of course, is not the same as there being sufficient evidence, on a Galbraith plus basis, for a coroner/jury to safely find that a matter was probably, or even possibly, causative of death (in the Tainton sense), nor that submissions cannot and should not be made at the conclusion of the evidence in this regard in an appropriate case.
The reason this article started with the concession of "mostly" was the Court of Appeal's use of the Sentencing Guidelines, and the suggestion of effectively stepping into the shoes of a sentencing court in assessing what would likely have occurred following arrest. Whilst it was not accepted on the facts of this case, the reality is that it may often be too speculative to predict what would likely happen following arrest (and other scenarios), and there is a danger that O'Brien will be used to push the speculative into the likely. Whilst IPs should, perhaps, take a pragmatic/cautious approach in terms of submissions as to scope at a preliminary stage, this risk should be particularly guarded against in submissions at the conclusion of the evidence.
Disclosure. The Court of Appeal was critical of the Chief Constable not having disclosed Mr McMahon's antecedents within the coronial or JR proceedings. This highlights a tension, and difficulty, for IPs in two respects:
- An individual's antecedents is not an unknown unknown (particularly on the facts of this case); all know it exists. It will not always ordinarily form part of a police force's disclosure within coronial proceedings. If the IP has not considered it relevant, and HMC has not directed its disclosure (particularly if it has been requested by another IP), then, relevant evidence being a matter for the coroner, how far is that IP supposed to go?
- Between the coronial and JR proceedings. If an IP has requested a document within coronial proceedings, and the coroner has not directed its disclosure (whether to the court in the first instance, or for onward disclosure), where does that leave the IP in any subsequent JR proceedings, in which, again, that document is requested, particularly if there is no direct challenge to the evidential decisions made by the coroner? Is the IP to go behind the coroner's decision? Is there a tension with the duty of candour in JR proceedings? Each case will turn on its facts, perhaps dependent upon how central the document may or may not be, but the safest course will usually be to have provided the document to the coroner for him/her to determine its relevance in the first instance.
Costs. There are plainly take-aways for both coroners and IPs:
- For Coroners –
  - Neutral means assisting the court neutrally on matters of law, procedure and fact (in so far as ensuring the court has before it all of the relevant facts). Defence of the coroner's decision in any way, even amongst protestations of neutrality, may attract an unfavourable costs order. This may be a difficult tightrope to walk, given the Supreme Court's suggestion in Maguire for counsel for the coroner to go beyond setting out the legal framework, in providing "full argument to understand the detailed factual circumstances of the case and how they might bear upon the issues in the appeal", albeit acknowledging that such argument need not be inappropriately adversarial.
  - The position adopted in pre-action correspondence is relevant, and the coroner is not required therein to justify and explain his/her decision-making.
- For IPs –
  - Submissions made at an early stage in coronial proceedings can have a bearing in subsequent JR/appeal proceedings, if they have been erroneously accepted. This does appear to be a harsh point, and a tricky judgment call for those representing (particularly given that the High Court had plainly not considered it an unreasonable argument to make).
  - An IP's approach to disclosure is relevant to the issue of costs.n this article, Lujzka Halsall-Fischel considers the implications of the recent decision in R (on the application of Sharon O'Brien) v HM Assistant Coroner for Sefton, Knowsley and St Helens and The Chief Constable of Merseyside Police (Interested Party) [2026] EWCA Civ 499. Lujzka is joint Deputy Head of the Hundred Court Chambers Inquests and Inquiries group, and specialises in inquests, police law and clinical negligence.

Dated 14th June 2026.

LUJZKA HALSALL-FISCHEL
HUNDRED COURT CHAMBERS