Principles of Criminal Causation


The Doctrine of Causation explained

The doctrine of causation as we understand it is applied by the courts to determine the existence of a link or causal chain between a defendant’s conduct and a particular result prohibited by law.

As Simester explains:

‘Within the criminal law, causation doctrines govern the connection between D’s behaviour and consequence elements, if any, of an offence’.

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For instance, the question of whether the accused’s conduct of inflicting serious stab wounds on his victim caused the death of his victim is addressed by the courts, —

relying on not just legal principles but also moral assessments as to whether such a defendant is to be considered the factual and legal cause of the harm suffered by the victim.

Simester notes that principles of causation ‘articulate the paradigm route by which ascriptive responsibility for those occurrences can be attributed to D.’ (Simester 2017, p.416).

A question of whether the accused should be held morally and legally responsible for the harm that has ensued from his actions and therefore deserving of judicially sanctioned punishment. 

How is such causal responsibility for criminal liability assessed and justified by the courts? This essay argues that the courts in drawing from moral and ethical considerations when determining criminal responsibility are disinclined to merely rely on a non-normative,  ‘mechanical’  approach to the application of legal principles.

As Simester observes, academics today tend to apply ‘a two – step inquiry ’ beginning with a ‘non-normative’ or factual test for causation which sets the preliminary stage for inquiring whether the particular harm suffered by the victim would not have occurred ‘but for’ the defendant’s conduct.

The second line of analysis is ‘normatively sensitive, in that it is informed by morally salient considerations, including novus actus doctrines.’ ( Simester 2017, p418).

As Wilson argues, ‘abandoning the causing of harm as a focus for criminal responsibility , would, however, ignore a major retributive concern.’ (Wilson, p.102).

It is arguable that retributive forms of justice dispensed by the courts for harm caused to society are guided not only by the need to vindicate the rights of victims of crime but to do so in a way that is morally and legally justifiable.

Thus a paradigmatic approach that incorporates the novus actus doctrine is applied to consider whether variables such as medical negligence, victim’s refusal to accept life saving medical treatment and foreseebility of harm suffered by the victim act to break the causal link.

Michael Moore argues that ‘justice is achieved only if the morally responsible are held liable to punishment’ and ‘if moral responsibility depends in part on causal responsibility then ‘cause’ in law must mean what it means in morality.’ ( Moore, p.5)

Thus, we note that the causal framework provides the instrument in criminal law by which one ascertains the moral and therefore the legal responsibility of individuals for harm caused to another.

Prof. Wilson explains:

having a causal requirement allows to put on record how the victim was wronged , and reflect the extent of the harm done in punishment’ ( Wilson, p. 102).

It is arguable that the calibration of justice in contemporary criminal justice systems reflects the doctrine of proportionality underpinning the just deserts theory on punishment:

the idea that the punishment should fit the crime.

Alan Norrie further explains that ‘in causation, the central notion is of something which interferes with or intervenes in the course of events which would otherwise occur

Human beings are able to manipulate things, to move and change them, so that where an individual has acted, she is said to have caused any changes that occur, and responsibility for the changes can be imputed to her.’ (Norrie, p.689)


The Empirical or Factual nature of Causal attribution  

An empirical or factual cause is explained by Hart and Honoré as—

 ‘an event or act which ‘makes the difference’ between something happening and something not happening. (Causation and the law.’ (1959).

Prof William Wilson clarifies that:

an act is the factual cause if the consequence would not have happened but for that act’.

Put another way, if the consequence would have happened just as it did irrespective of the defendant’s act (White [1910] 2 KB 124) or omission (Morby 1882).

So White was not deemed to be the cause of the death of his mother, whose drink he had poisoned, when she suffered a cardiac arrest and died before taking the poison.


Legal causation (The evaluative nature of causal attribution)

The factual cause of a consequence will also be the legal cause of that consequence, unless the factual cause is too insubstantial or remote to render it inappropriate to attribute the consequence to the act. (Wilson)

This idea is exemplified by the Draft Criminal Code which clarifies that —

‘a factual cause will be too remote if, subsequent to it, another act or event occurs which also contributed to the result which was not foreseen by the defendant, —

and could not in the circumstances reasonably have been foreseen.’ (Clause 17, Draft Criminal Code Bill 1989).

Following this perspective, the criminal courts engage in the evaluative process of determining whether the defendant’s conduct is the legal cause of a criminal harm.

This requires proof that the consequence must be the consequence not merely of the defendant’s act but of their wrongful act. (Prof.Wilson);

A doctrine exemplified in Adams (1957) in which a doctor gave his terminally ill patient a dose of painkillers so strong that it killed the patient.

Devlin J ruled that if the dose were given for pain relief in accordance with the doctor’s duty—

it would not be the doctor but the disease which was the real cause of death.

The doctor’s contribution could be ignored as negligible (Wilson).The death of the patient was therefore not deemed to be consequence of any wrongful or culpable conduct of the doctor.

How far may the actions of a third party break the chain of causation in result crimes? Analysing Smith 1959: The substantial contribution principle.

Lord Parker in Smith tells us if a third party contributes to the harmful result, this will not break the chain of causation—

if D’s original act was still a substantial and operative cause of the harm.

The archetypal case of R v Smith [1959] 2 QB 35 is illustrative of a finding of causation which is non- normative in that ‘it rests on a finding about the physical facts of the matter.’ ( Simester, p. 419).

Thus the facts of Smith account for the court’s decision. The fact that the stab wound to the victim’s lung was serious was evidenced by the uncontrollable bleeding that had not ceased at the time of the victim’s death.

Lord Parker found that the wound that punctured the victim’s lung was the operating and substantial cause of his death notwithstanding the fact that the victim had been dropped twice and had been deprived of an immediate blood transfusion.

Here, one may argue that the stab wound in itself was an immediate and direct cause of death, sufficient to kill the victim. As such, ‘we can ignore questions about whether any other actor in the drama was a novus actus interveniens: other causes can only be concomitant ones.’ (Simester, p. 419).

What exactly does the term ‘substantial’ cause mean?

One reading of the term suggests that it means ‘simply more than minimal’ (Horder, p.126) as inferred from cases such as Cato 1976 in which the Court of Appeal stated that a legal cause would be one that ‘was outside the de minimis range, and effectively bearing upon the acceleration of the moment of the victim’s death.’ (R v Cato (1976) 62 Cr App R 41).

The case of Smith 1959 could be contrasted with Jordan 1956 where the court found that ‘palpably wrong treatment’ was provided by the hospital to the victim whose wound had ‘practically healed.’

As a matter of common sense and logic, an attribution of the cause of death of the victim to Jordan could not have been supported —

since the wound inflicted by him on the victim no longer played any part in causing death, and was merely ‘part of the history’ or the ‘setting’ in which a second overwhelming cause of death exists. ( Smith 1959 applied).

In Smith  the victim died of a stab wound to the lung, but not before he had been dropped twice before reaching medical attention and had received artificial respiration. Smith was still the legal cause of V’s death.

Although the intervening acts contributed to the death, Smith’s acts were still a substantial cause of the harm and were still operative at the time of death. (Prof Wilson)

Simester further explains why a third-party’s contribution in the case of Smith 1958 did not break the causal link.

‘’Perhaps V would not have died but for the mistreatment. Be that as it may, D’s conviction of murder was rightly affirmed.

The original injury was still, as the court said, an “operating” cause of V’s death, in that the stab wound and consequent haemorrhage were immediate medical factors explaining V’s death, albeit alongside other contributions” (Simester 2017).

As Simester argues, the attribution of causation in the case of Smith was non-normative since ‘it rests on a finding about the physical facts of the matter’ or a forensic inquiry; Simester notes 

‘if we inquire forensically into the immediate physical cause of V’s death, ongoing loss of blood from the stab wound is part of the explanation’(Simester 2017).

Victim’s contribution to a break in the chain of causation

In Roberts (1972) 56 Cr App R 95, V jumped out of a moving car in reaction to being sexually assaulted by D in the car.

On the facts of this case the chain of causation between D’s conduct and V’s response and subsequent injury she suffered was not broken; 

The Court of Appeal ruled that D was the cause of V’s injuries –

 as D’s act began the causal chain and her reaction was reasonably foreseeable.

The Court also stated that the chain of causation would be broken only by the victim doing something ‘daft’.

Alan Norrie argues that cases such as Roberts exemplify the claim that ‘self-preservation negates the voluntariness of an action’ by a victim. (Norrie, p.694).

What may be problematic for the court in such cases is determining when a victim’s actions may be considered ‘daft’ and possibly involuntary.

This may raise a number of questions for the judge and jury to consider. As Norrie points out:

‘’in order to construe the actions of a woman as involuntary in those cases where minor molestation in a car in motion leads her to jump out to her injury or even death, —

it is necessary to have an understanding of the alarm experienced by women in sexual assault situations that judges do not always reveal.’’ (Norrie, p.694)

Pagett and Cheshire: Cases indicating how third-party or victim actions or reactions rarely break the chain of causation

The cases of Cheshire 1991 and Pagett 1983 are indicative of the fact that third-party or victim actions or reactions rarely break the chain of causation.

This is especially the case where the V or the third-party’s actions are not deemed by the court to be independent of the defendant’s conduct.

Both cases of Pagett and Cheshire illustrate the requirement that the act of the third party be independent of D’s act.

The acts of the police officers in Pagett, and the medics in Cheshire, did not involve new acts intervening because they were by way of reaction to D’s wrongful act.

They were not independent of it. (Wilson).

Additionally, Norrie argues that Criminal law policy has a role in ‘structuring the perceptions and establishing the breadth of the frame of analysis’ in cases such as Pagett, —

a case in which ‘police officers kill third parties in attempts to control those involved in crimes of violence, and causal responsibility is imputed to the latter’. (Norrie p.694)

The Court of Appeal in Pagett went on to state:

”if a reasonable act of self-defence against the act of the accused causes the death of a third party…[it does not] relieve the accused from criminal responsibility for the death of the third party.”

In Pagett (1983) 76 Cr App R 279, D used his pregnant girlfriend, V, as a human shield to prevent police officers arresting him. D had a shotgun with him and shot towards the police. They returned fire and V was killed.

He appealed against conviction for manslaughter on the ground that the police, and not he, had caused V’s death. The Court of Appeal disagreed.

In reaching its decision it said: if a reasonable act of self-defence against the act of the accused causes the death of a third party…[it does not] relieve the accused from criminal responsibility for the death of the third party

In the case of Cheshire [1991] 1 WLR 844  D shot V in the abdomen. V was taken to hospital where he was operated on.

Almost immediately he started suffering breathing difficulties and so a tracheotomy was performed.

Six weeks later, V’s wounds were nearly healed but his breathing was getting progressively worse and he died.

The doctors failed to recognise and respond to the cause of V’s problems, which was that the tracheotomy had been negligently performed.

The trial judge told the jury that this bad medical treatment did not relieve D from responsibility. On the basis of this direction the jury convicted. D appealed.

Beldam LJ speaking in the CA stated that—

‘it would only be in the most extraordinary and unusual case that the accused would not be responsible for injuries or death suffered by medical treatment ‘attempting to repair the harm done.’

Wilson notes that this was not an extraordinary and unusual case, because it is in the nature of medical treatment that action directed to alleviate one medical problem may precipitate another.

Additionally, ‘death occurring due to incompetent medical treatment is within the range of risks created by the defendant’s action.’ (Wilson p.114 applying R v Warburton 2006 CA).

The first appellant (W) appealed against his conviction for manslaughter and the second appellant (H) appealed against his conviction for murder. W, H and codefendant had been charged with murder.

A pathologist gave evidence that the victim had died from a combination of knife wounds, blunt force injuries and drowning.

W claimed that he had slapped the victim twice at the request of his codefendants to avoid being beaten himself and had taken no further part in the violence.

W further contended that the judge had wrongly failed to direct the jury that if it found that his account was true or might have been true, he could not be convicted of either murder or manslaughter.

The Court of Appeal held that held that the jury should have been directed in terms that if W’s involvement had ceased after the two slaps, or might have ceased at that point, then he could not be guilty of either murder or manslaughter.

In the absence of such guidance, the verdict could not be regarded as safe and had to be quashed.

The Thin skull rule in Blaue compared to the Draft Criminal Code rules and the Common law rules on Causation   

The Thin skull rule or ‘Egg shell skull case’ applying the rule ‘take your victim as you find her’ is exemplified in cases such as Blaue and Holland.

In Holland (1841) 2 Mood & R 351, V, following a serious assault with an iron bar, refused to submit to the amputation of a finger, recommended to prevent tetanus.

D was held to be causally responsible for V’s resultant death from tetanus.

In Blaue [1975] 1 WLR 1411, D stabbed V, causing serious blood loss. Doctors treating V told her she needed a blood transfusion else she would die.

V refused the transfusion for religious reasons and died of blood loss. D argued that he was not the cause of V’s death: the cause was V’s refusal.

The Court of Appeal rejected this argument, stating that the defendant must ‘take the victim as he finds him’.

It is to be noted that D’s act of stabbing the victim was still a substantial and operative cause of death (per Lord Parker in Smith 1959)

The victim’s wounds were also a more than negligible cause of death as indicated by the post-mortem report.

Such findings suggest that clause 17 of the Law Commission Draft Criminal Code 1989 was satisfied:

‘a person causes a result which is an element of an offence when (a) he does an act which makes more than a negligible contribution to its occurrence’

Norrie considers the argument that ‘a condition like the eggshell skull gains its significance from the fact not that it is contemporaneous with the act of assault,–

but from the fact that it pre-exists the act in question:

it is part of ‘the stage already set’ as Hart and Honore put it.’

Norrie, however, argues that such a ground for causal analysis is too inadequate because –

  • ‘the issue still has to be faced as to whether or not the pre-existing condition is normal or abnormal.

Norrie asserts that:

‘A condition is irrelevant to causal attribution where it is a ‘mere’ condition, that is, one that is ‘present both in the case of the disaster and of normal functioning,’ or is a ‘normal feature of the thing in question.

‘The ‘mere’ condition is the one that does not ‘make any difference’ between the accident and things going on as usual.’ (Norrie, p.700)

Novus Actus Interveniens

Existing between the spectrum of cases where an unbroken causal chain remains between the defendant’s conduct and the harm suffered by the victim, and those where the defendant’s conduct is relegated to the background facts, —

lies those problematic cases where novus actus interveniens or a new intervening voluntary act of a third party is argued to arise.

Wilson argues that ‘one way of explaining this rule is that it is an example of the general principle that the defendant will only be responsible for harms occurring within the risk created by the defendant’s act.’ (Wilson, p. 112) .

A case in point is Rafferty 2007 where the Court of Appeal held that ‘the drowning of (V by the others)…was so completely different from the injuries for which Rafferty was responsible, that it overwhelmed those injuries and destroyed any causal connection between them and the death of V.’ ( Wilson p.113) .

As Simester argues ‘C causes E whenever there is a continuing physical reaction chain from C to E ….doing so allows us to acknowledge a form of causation that is not amenable to being defeated by a novus actus interveniens.’ (Simester, p.426).

It is arguable however, that such a ‘continuing physical reaction chain’ was absent on the facts of Rafferty where the accused left the scene of the initial assault of the victim leaving the other assailants to drag the victim to the sea and drown him.

Moore notes that-

To intervene between defendant’s act and his victim’s harm, an event must not itself be the product of defendant’s act. If it is such a product, then the event is merely part of the mechanism or means by which defendant’s act caused the harm; it is not an intervention preventing such causation by defendant.’

Hart and Honoré give this example: ‘’a defendant who culpably pushes his victim to the ground is not liable for that victim’s death when the victim is killed on the ground by a falling tree. The falling tree, in such a case, intervenes between defendant’s push and the victim’s death.

By contrast, if the defendant’s push caused the victim to stagger into a rotten tree, and the impact caused the tree to fall and kill the victim, the defendant is held to have caused the death. While the tree’s falling was subsequent to the defendant’s act of pushing, it was not causally independent of the push and so does not constitute an intervening cause.” ( Moore, p.237)

Evaluating the competing tests of causation – namely those asserting that unforeseeable acts/events break the chain, —

and those asserting foreseen and foreseeable actions of V or T break the chain of causation if voluntary. (Kennedy, Rafferty, Wallace)

In Finlay [2003] EWCA Crim 3868 the Court of Appeal said that the supplier of classified drugs had caused the death because it was foreseeable that the recipient would self-inject.

The position now, following Kennedy (No 2) [2007] UKHL 38, is that the test is—

not whether the victim’s act was foreseeable but whether it was voluntary.

A free and informed choice to self-inject the drug breaks the chain of causation.

It would not be free and informed if the victim lacked mental capacity or did not know of the strength of the drug.

The House of Lords in Kennedy went on to state that:

“The criminal law generally assumes the existence of free will.

The law recognises certain exceptions, in the case of the young, those who for any reason are not fully responsible for their actions, and the vulnerable, and it acknowledges situations of duress and necessity, as also of deception and mistake.

But, generally speaking, informed adults of sound mind are treated as autonomous beings able to make their own decisions how they will act, and none of the exceptions is relied on as possibly applicable in this case.”

Thus D is not to be treated as causing V to act in a certain way if V makes a voluntary and informed decision to act in that way rather than another.”

Simester, however, questions such a conception of causal responsibility:

Are not even free, deliberate, and informed interveners sometimes predictable?

If the intervention…was reasonably foreseeable, surely it would not count as extraordinary?

Even if we cannot trace direct causation through the complexity of T’s dispositions, can we not locate a form of indirect causation here? (Simester p.16).

Simester further posits that:

‘The rule is normative rather than metaphysical. Underpinning the FDI rule is what I have elsewhere called the principle of personal control over criminal liability, —

according to which no-one should have the power deliberately to render another person guilty of a crime.

Our liability, like our culpability, flows from what we do (or omit to do).

It does not, and should not, spring from the choices of others.’ (Simester p.16).


As Prof Glanville Williams states:

‘I may suggest reasons for you to do something. I may urge you to do it; my efforts may perhaps make it very much more likely that you will do it.

But they do not cause you to do it in the sense in which one causes a kettle of water to boil by putting it on the stove.’

Prof Herring provides a cogent analogy to illustrate the doctrine of free will:

‘If I take my kleptomaniac friend shopping, I may foresee that she will shoplift, but does not mean that I cause the shoplifting.’


The case of Rafferty [2007] EWCA Crim 1846.

In Rafferty D was party to a joint enterprise to beat V.  D withdrew from the attack after delivering some blows and kicks and left the scene.

His co-attackers eventually stripped V naked, dragged him into the sea and drowned him.

The Court of Appeal approved the trial judge’s direction to the effect that:

‘the drowning of the victim by the others….was so completely different from the injuries for which Rafferty was responsible , —

that it overwhelmed those injuries and destroyed any causal connection between them and the death of the V.’


 In R v Wallace [2018] EWCA Crim 690, —

A victim committed suicide some two years after being attacked by the defendant who threw concentrated sulphuric acid over him while he was sleeping. The attack left the victim blind, paralysed and in excruciating  pain. 

Two years later he checked into a euthanasia clinic in Belgium where euthanasia is legal and his life was terminated. He had decided that he could not continue to live with his injuries and the pain.

 The defendant was charged with murder and the trial judge refused to allow the question of causation to be considered by the jury on the ground that there was too long a delay between the act and the death.

 The jury brought a conviction of throwing corrosive fluid on a person, with intent to do grievous bodily, an offence under s.29 of The Offences Against the Person Act 1861.

Prof Wilson: The Court of Appeal ruled that the trial judge was wrong to withdraw the question of causation from the jury.

 It was open to the jury to conclude that, despite the time between the throwing of the acid and the death, —

the acts of the victim were a direct response to the injuries inflicted for which the defendant was directly responsible.

The question to be considered in all cases where more than one cause contributed to the death is —

whether ‘the accused’s acts can fairly be said to have made a significant contribution to the victim’s death’.

 A retrial was ordered and in June 2018 the jury again acquitted of murder and convicted of the s.29 offence. Clearly, they were not convinced that murder was the appropriate offence.( Prof W. Wilson

The case of Wallace reminds us that questions of causation continue to be influenced by ethical, moral assessments of criminal responsibility, intuitively assessed by a jury in applying their sense of jury justice.

Patrick J.



A Critique of Criminal Causation : Alan Norrie : The Modern Law Review, Vol. 54, No. 5 (Sep., 1991), pp. 685-701.

Simester, A.P. Law Quarterly Review, 2017, Vol.133, pp.416-441.

Wilson W., Criminal Law, 2017, Pearson, 6th Edition

Herring Jonathan , Great Debates in Criminal Law, Palgrave,  3rd Edition.

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