R v Cosier: When Loss of Control Need Not Be Left to the Jury and How “Imperfect” Self-Defence/Provocation Should Mitigate Schedule 21 Minimum Terms

Introduction

R. v Cosier ([2026] EWCA Crim 2) is a decision of the Court of Appeal (Criminal Division) dealing with (i) the threshold for leaving the partial defence of loss of control to the jury under ss.54–55 of the Coroners and Justice Act 2009, and (ii) the correct approach to mitigation when fixing the minimum term for a mandatory life sentence under the Sentencing Act 2020.

The appellant was convicted of murder after fatally stabbing a stranger outside a public house following an escalating confrontation in which the deceased fired a BB gun. At trial, the central defence was self-defence. Post-evidence, the defence sought to add an alternative verdict route of manslaughter by loss of control; the trial judge refused to leave that partial defence to the jury. On appeal, the conviction challenge focused solely on that refusal. The appellant also renewed his sentence challenge.

A reporting restriction under s.45 Youth Justice and Criminal Evidence Act 1999 protected the identity of a child witness, and the Court confirmed continued anonymity in the judgment.

Key issues

Conviction: Was there “sufficient evidence” of loss of control such that a jury, properly directed, could reasonably conclude the partial defence might apply, requiring it to be left to them?
Sentence: Even with a 25-year starting point accepted, did the judge give adequate weight to mitigation, particularly “provocation” and “self-defence falling short”, and was the minimum term manifestly excessive?

Summary of the Judgment

Conviction appeal

The Court of Appeal dismissed the conviction appeal. It held that the trial judge correctly concluded there was no sufficient evidence that the killing resulted from a loss of self-control within s.54(1). In particular: (i) the appellant did not assert loss of control and positively portrayed himself as rational and defensive; (ii) alleged memory gaps did not supply a proper evidential basis to infer loss of control; (iii) CCTV and surrounding conduct showed purposeful, deliberate behaviour inconsistent with the statutory concept.

Sentence appeal

The Court granted an extension of time and leave, allowed the sentence appeal, and reduced the minimum term from 25 years (less remand) to a notional 22 years (less 231 days remand), resulting in 21 years and 134 days. The Court found the original minimum term was manifestly excessive because the sentencing judge failed to credit additional mitigation, notably significant provocation and “self-defence falling short” as recognised mitigating factors in Schedule 21.

Analysis

Precedents Cited

1) R v Goodwin [2018] EWCA Crim 2287, [2018] 4 WLR 165

Goodwin supplied the governing framework for a judge deciding whether loss of control should be left to the jury: the judge must undertake a “rigorous evaluation” of the evidence and make a common-sense judgment on whether the statutory threshold is met. It also warns against “cluttering up” the jury’s task by leaving defences that do not arise on the evidence, and treats it as a “powerful point” against leaving the issue where the defendant does not assert loss of control in evidence.

In Cosier, both the trial judge and the Court of Appeal used Goodwin to justify a firm gatekeeping role: absence of an asserted loss of control, coupled with evidence of deliberate actions, can mean the statutory threshold in s.54(6) is not crossed.

2) R v Turner [2023] EWCA Crim 1626, [2024] Crim LR 339

Turner reiterates that the judge must not simply substitute their own view of the evidence; rather, they must evaluate what findings are reasonably open to a jury. The appellant relied on Turner to argue the trial judge decided matters (e.g., whether the attack was “frenzied”) that should have been left to the jury.

The Court in Cosier effectively held that, even applying Turner, the evidential foundation required by s.54(6) was absent: the inferences necessary to reach loss of control were not “properly open” on the evidence, particularly in light of CCTV and the appellant’s own account.

3) R v Jewell [2014] EWCA Crim 414

Jewell provides a functional definition of loss of control: a loss of the ability to act in accordance with considered judgment or normal powers of reasoning. This definition mattered because the appellant’s case, as presented, was consistent with considered (if unlawful) decision-making: arming himself, going outside, and acting with purpose.

The Court applied Jewell to distinguish a person who “stops exercising restraint” from a person who loses the capacity for considered judgment in the statutory sense.

4) R v Dawson [2021] EWCA Crim 40

Dawson cautions that sustained or gratuitous violence does not, by itself, provide sufficient evidence of loss of control. In Cosier, the point supported the Court’s conclusion that neither the nature of the violence (a single fatal stab wound with a separate slashing injury) nor the CCTV chase automatically translated into a statutory loss of control. The focus remained on whether there was evidence of an actual loss of the ability to reason or act on considered judgment.

Legal Reasoning

A. The “sufficient evidence” threshold under s.54(6)

The critical statutory gateway is s.54(6): whether there is evidence on which, in the trial judge’s opinion, a jury, properly directed, could reasonably conclude that the defence might apply. The Court treated this as a real threshold—not a presumption that partial defences should be left “just in case”.

B. No asserted loss of control, and a positively “rational” account

A defining feature in Cosier was that the appellant did not say “I lost control” (or anything materially similar); instead, he portrayed himself as acting rationally and defensively throughout. Following R v Goodwin [2018] EWCA Crim 2287, [2018] 4 WLR 165, the Court endorsed the proposition that this is a powerful reason not to leave loss of control.

C. “I can’t remember stabbing” is not, without more, evidence of loss of control

The Court rejected the argument that an asserted lack of recollection could be treated as a lay description of loss of control. In this case it was “just that”—an asserted memory gap—especially when set against the appellant’s claimed clarity about the surrounding events that supported self-defence.

This part of the reasoning is practically important: it tightens the evidential discipline around what can count as a basis for leaving loss of control, preventing the partial defence from being invoked through ambiguity or forensic opportunism where the defendant’s primary narrative is calculated, defensive action.

D. Rational conduct before and after the killing as probative of state of mind at the moment

The Court approved the trial judge’s use of the appellant’s conduct immediately before and after the stabbing (arming himself, repeatedly going outside holding the knife, post-incident actions including leaving the scene and acquiescing in disposal of the knife) as evidence bearing on whether there was a loss of control at the critical time.

Importantly, the Court did not say rational conduct always defeats loss of control; rather, it accepted it was appropriate to treat it as relevant evidence undermining an inference of a sudden, momentary loss of the ability to reason in a case where the defendant’s own account was of purposive conduct.

E. CCTV and the rejection of “frenzy” as a route to loss of control

Having reviewed the CCTV, the Court agreed it depicted a short, intense chase with a brandished knife but did not provide a basis to infer the statutory loss of control. A child witness’s observation that the appellant “didn’t seem to react at all” to BB shots further weakened the suggested inference that fear induced a collapse of reasoning capacity.

F. The Court’s restraint on other elements of the defence

The trial judge also dealt with qualifying trigger, s.55(6)(a) (incitement), and the objective tolerance/restraint limb, but the Court held that, once the threshold “loss of control” element failed for lack of sufficient evidence, it was unnecessary to decide the remaining arguments to resolve the conviction appeal.

G. Sentencing: intention to kill upheld; mitigation recalibrated

On sentence, the Court upheld the judge’s factual finding of intention to kill, noting independent evidence of the appellant shouting “I’ll kill you. You’re dead”. It also accepted the relevance of aggravating features (public place, disposal of weapon, intoxication, antecedents).

The appellate intervention came from the Court’s view that the judge did not sufficiently recognise mitigation expressly contemplated by Schedule 21: provocation and self-defence falling short of a full defence. The Court treated the deceased’s conduct (arriving intent on confrontation; producing and firing a BB gun at the appellant’s face/body) as significant provocation, and accepted there was a realistic “imperfect self-defence” flavour even though the full defence failed.

The Court also placed weight on the nuance that the appellant did not arrive with a knife; he obtained one from the pub kitchen, supporting a conclusion that this paragraph 4/Schedule 21 case was not at the top end of seriousness within the 25-year category. The result was a reduction to a notional 22-year minimum term.

Impact

1) Loss of control: reinforcing robust judicial gatekeeping

Cosier strengthens the practical message from Goodwin: trial judges should leave loss of control only where there is a concrete evidential platform for the statutory concept—loss of the ability to act on considered judgment— not merely evidence of anger, fear, escalation, or violence. The decision confirms that:

A defendant’s failure to assert loss of control, especially where they affirm rationality, can be decisive at the s.54(6) stage.
An asserted memory gap will not ordinarily be enough to “bootstrap” loss of control into the case.
Pre- and post-incident conduct can properly be used to assess whether the statutory loss of control is evidenced at the moment of killing.

2) Tactical consequences for defence presentations

The case illustrates a tension between running self-defence (often involving claims of assessment and protective intent) and later seeking to add loss of control. Where the defendant’s evidence is framed as measured and defensive, it may foreclose the factual basis necessary to leave loss of control.

3) Sentencing: concrete weight to Schedule 21 mitigation within high starting points

On minimum terms, Cosier underscores that even where the starting point is agreed (here 25 years), the sentencer must still engage fully with Schedule 21 mitigation, including:

Provocation that does not meet the loss of control partial defence threshold.
Self-defence falling short of the full defence (sometimes described as “imperfect self-defence”).

The decision shows appellate willingness to intervene where those statutory mitigators are present on the facts but not adequately reflected in the term selected.

Complex Concepts Simplified

Partial defence of loss of control (ss.54–55, Coroners and Justice Act 2009): A mechanism that can reduce murder to manslaughter if (1) the defendant lost self-control, (2) there was a qualifying trigger (e.g., fear of serious violence), and (3) an objective “normal tolerance and restraint” person might have reacted similarly in the circumstances.
“Sufficient evidence” (s.54(6)): Not “any evidence” or “a speculative possibility”. It means evidence on which a properly directed jury could reasonably conclude the defence might apply. The judge must screen out defences with no proper evidential foundation.
Loss of control vs losing restraint: You can act violently, angrily, or impulsively without losing the capacity to act on considered judgment. The statutory concept is narrower: it is about a loss of the ability to reason/choose in the ordinary way.
Self-defence falling short (sentencing mitigation): Even if self-defence fails legally (e.g., disproportionate force), the fact the defendant may have perceived a threat can mitigate sentence because it reduces moral culpability compared with unprovoked aggression.
Manifestly excessive: An appellate standard meaning the sentence is outside the range of reasonable sentences open to the judge, warranting interference even though sentencing is usually discretionary.

Conclusion

R. v Cosier reaffirms that loss of control is not a “fallback” to be left whenever there is fear, intoxication, or escalating violence. The defence must be grounded in evidence of the statutory kind of loss—an inability to act in accordance with considered judgment—and judges are entitled (indeed required) to prevent the jury’s task being burdened by unsupported partial defences.

At the same time, the case demonstrates that where murder attracts a high Schedule 21 starting point, sentencing must still meaningfully credit statutory mitigation such as provocation and self-defence falling short, even if those matters do not succeed as defences at trial. The Court’s reduction of the minimum term signals careful appellate scrutiny where such mitigation is factually present but insufficiently reflected in the final term.