“The Murphy Adjustment” – Calibrating Sentences for Non-Terrorist Explosive Offences that Resemble Terrorism

Introduction

The England and Wales Court of Appeal (Criminal Division) decision in Murphy, R. v ([2025] EWCA Crim 992) addresses how sentencing courts should approach serious explosives offences which, while lacking a terrorist ideology, manifest many of the objective features of terrorism. Alan Murphy, a 62-year-old drifter with an extensive history of firearms offences, pleaded guilty to possession of a viable improvised explosive device (IED), two imitation firearms and a bladed article. His professed intention was to damage an HSBC branch after watching a Netflix documentary. At first instance he received an extended sentence of 20 years (15 years’ custody, 5 years’ extension). On appeal he challenged the length of the custodial term, arguing in essence that the judge over-imported the Terrorism Guideline into a non-terrorist case.

The Court of Appeal dismissed the appeal but, in doing so, set out a structured approach— here dubbed “the Murphy Adjustment”—to determine how far courts should step away from the Terrorism Guideline when sentencing analogous yet non-terrorist explosive offences.

Summary of the Judgment

The Crown Court was entitled to adopt the Sentencing Council’s “Explosive Substances (Terrorism Only)” Guideline as an analytical starting point even though the offence was not terrorism-related.
The crucial sentencing exercise is a fact-sensitive adjustment that weighs: (1) overlap with terrorist characteristics, (2) breadth of criminality, and (3) public risk.
Where opposing considerations (e.g., risk of death versus absence of ideology) “cancel each other out”, the court may revert to the guideline’s original starting point.
In Murphy’s case, the Court of Appeal found no error in the trial judge’s methodology: 16-year starting point → +4 years for aggravation → 25 % discount for plea = 15-year custodial term, properly forming part of a 20-year extended sentence.
The appeal on all five grounds was therefore dismissed.

Analysis

1. Precedents Cited

R v Muhammed [2017] EWCA Crim 1832 was the pivotal authority. In Muhammed, the Court endorsed the use of the Terrorism Guideline for Section 3 Explosive Substances Act offences, even when the facts fell outside a statutory definition of terrorism, provided the court made an appropriate adjustment. Murphy builds upon—and refines—that reasoning by supplying explicit criteria for the adjustment exercise.

The judgment also referenced:

Sentencing Act 2020 – particularly s.63 (assessment of seriousness) and s.69 (terrorist connection determinations).
Explosive Substances Act 1883, s.3(1)(b) – the substantive offence.
Sentencing Council Guideline: Explosive Substances (Terrorism Only), Categories A–C, Harm Levels 1–3.

2. The Court’s Legal Reasoning

The Court of Appeal endorsed the first-instance judge’s four-stage structure:

Identify the lead offence (Count 1, possession of a viable IED).
Choose an analytical anchor (Terrorism Guideline, Category 3A: 16-year starting point).
Apply “Murphy Adjustment” factors:
- Degree of similarity to a terrorist offence (media attention, public fear, coercive intent).
- Scale of criminality (additional weapons, prior absconding).
- Nature and magnitude of risk (risk of death identified as “inevitable”).
In casu, the absence of ideology offset the enhanced risk of death. Net effect: no movement from 16-year starting point.
Aggravation & Mitigation: Prior convictions, unlawful absconsion and concurrent weapon counts justified +4 years; systemic plus defendant-specific delay only partially mitigated. A 25 % plea credit then yielded 15 years.

Notably, the Court clarified that judges are not compelled to record granular numerical adjustments at every micro-step. Sufficiency of reasoning—not arithmetical transparency—is the benchmark on appeal.

3. Impact of the Judgment

Codifies “Murphy Adjustment”. Future courts now have a tripartite test for discounting the Terrorism Guideline when ideology is absent.
Reinforces Flexibility. Sentencers may import terrorism guidelines into analogous crimes, provided they articulate a principled adjustment.
Upholds Robust Sentencing for Weaponised Grievances. The decision signals that self-styled “lone actor” protest violence—even if non-ideological—will attract sentences near terrorism ranges when risk to life is high.
Appellate Review Threshold Clarified. The Court will not interfere merely because a judge fails to showcase a line-by-line arithmetic; adequacy of the overall explanation suffices.
Prevents Double-Counting Anxiety. The Court’s treatment of ground 4 underscores vigilance against double-counting but affirms that concurrent sentences can still aggravate the lead-count’s starting point.

Complex Concepts Simplified

Extended Sentence: A hybrid sentence combining a custodial term and an “extended licence” period during which the offender is supervised; designed for dangerous offenders.
Starting Point vs. Category Range: Sentencing Guidelines give a numeric midpoint (starting point) and a band (category range). Judges calibrate upward/downward within the range after considering specific facts.
Terrorist Connection (s.69 SA 2020): A statutory mechanism that, if invoked, can increase maximum penalties or trigger special sentencing regimes. Lack of such a connection here necessitated the adjustment exercise.
Double-Counting: The appellate concern that the same fact is used more than once to aggravate a sentence (e.g., both as a standalone offence and as an aggravating feature of another count).
Viable vs. Non-Viable Device: A “viable” explosive device is capable of functioning and causing harm; courts treat possession far more seriously than for a non-viable device.

Conclusion

Murphy crystallises an important sentencing doctrine: where a defendant’s conduct apes terrorism in its objective risk profile but lacks ideological motive, judges should start with the Terrorism Guideline, then conduct a fact-sensitive “Murphy Adjustment” based on similarity, criminal breadth and public risk. If opposing factors neutralise one another, courts may stay at the terrorism starting point; otherwise, they must transparently justify any departure. The judgment reaffirms appellate tolerance for qualitative reasoning over mathematical narration, while spotlighting society’s heightened intolerance for DIY explosives—ideological or otherwise. In short, Murphy will likely serve as the go-to authority for calibrating sentences in the growing class of “pseudo-terrorist” explosive offences driven by personal grievance rather than extremist ideology.