An introduction to criminal law
Monday, 19 January 2026 18:12
R v Wallace 2018:
The victim in this case was a Mark van Dongen, who was a Dutch
national, living and working in the Bristol area as an engineer. He and
the defendant, Berlinah Wallace, had been in a relationship which had
broken up. The victim had visited the defendant at her flat, at her
request and had ended up staying the night. Whilst he was asleep, the
defendant threw sulphuric acid on him with the words; “If I can’t have
you, no one else will”. His injuries were so horrific the jury was not
allowed to see photographs of him on his arrival at hospital or during
his treatment.
He had full thickness burns to 25% of his body, was in a coma for 4
months, lost the sight in one eye and most of the sight in the other, his
lower left leg had to be amputated and he was paralysed – at one
point, only being able to move his tongue. Mark was eventually
discharged to a care home, where he was found in a dreadful state by
his father, who organised a private ambulance to take him to a hospital
in Belgium.
After developing further complications, Mark applied for euthanasia,
which is legal in Belgium and his request was granted. He died on 2
January 2017.
The defendant was originally charged with an offence of applying a
corrosive substance with intent.
1. An offence is (allegedly) committed
2. A police investigation takes place (including arrest, detain,
interrogations)
3. The police and CPS decide whether to prosecute
4. The prosecution and defence begin preparing the case
5. The trial (if D is pleading not guilty)
6. Sentencing if D is convicted (or pleads guilty)
7. Appealing against sentence or conviction (or against the judge’s
ruling)
Criminal behaviour is established in accordance to societal values and
views at the time. Thus, it is changing, and evolving over time and what
is criminal is not always constant. Eg adulatory and homosexuality was
illegal before, whereas stalking and cyber fraud is recent.
Statutory offence - criminalised behaviour under statutes passed by
Parliament
Common law offence - criminalised behaviour under precedence, such
as murder
The burden and standard of proof
The legal burden of proof is on the Prosecution to prove all the
elements of the offence, including disproving the defence.
The standard of proof is beyond a reasonable doubt, so that the jury or
magistrates should convict only if they are sure of the defendant’s
guilt - Woolmington v DPP [1935] AC 462.
The evidential burden is also on the Prosecution to provide sufficient
evidence to show that the accused has a case to answer and to justify
a finding of guilt.
However, there are some (rare) instances where the defendant has
either the legal or the evidential burden of proving their defence.
Actus Reus
The actus reus elements of an offence are every element within the
definition of the offence which is not related to the state of mind of the
defendant – Nicola Monaghan Textbook on Criminal Law Directions 7th
edition (Oxford University Press).
- Guilty act or guilty omission, everything that makes up the crime
apart from the mental stuff, mens rea. Building block.
- Varies from offence to offence, find it in the statute or common
law
3.1 Some general principles
3.1.1 Voluntary conduct
Where the actus reus is defined so as to require conduct on the part of
the accused, the conduct must be voluntary if it is to be criminal.
3.1.2 State of affairs crimes
Some offences do not require any conduct at all and are defined so
that the actus reus is simply the existence of a state of affairs. Eg
crashing due to a bunch of bees.
For example, s.4(2) of the Road Traffic Act 1988 which makes it an
offence to be in charge of a motor vehicle on a road or other public
place while unfit to drive through drink or drugs.
3.2 Omissions - will only be charged if you had a duty to act but
failed
Although most offences are defined so that the actus reus is an action
or the existence of a state of affairs, in certain criminal offences the
definition of the actus reus is such that it may also be committed by
omission.
General rule
A defendant will only be criminally liable for an omission if the law
recognises that they were under a duty to act and they failed to do so.
Exceptions to the general rule - statutes or common law (duty
situations)
3.2.1 Some statutory offences:
- s.7 Road Traffic Act 1988 – failing to provide a specimen of
breath
- s.170(4) Road Traffic Act 1988 – failing to stop and report an
accident
3.2.2 Duty arising out of contract:
R v Pittwood (1902) 19 TLR 37
If you have a contractual duty to a person but you fail to do so, you
could file yourself liable,
- Left the gate open during lunch break and someone died
3.2.3 Duty arising out of relationship:
R v Gibbins and Proctor (1918) 13 Cr App R 134
- Eg, parent and child, spouses, based on aid,
The father of the child starved the kid, charged based on relationship
3.2.4 Duty arising out of assumption of care for another:
R v Instan [1893] 1 QB 450, R v Stone and Dobinson [1977] QB 354
- You made it your business, once you assume care for another
you establish a duty.
3.2.5 Duty arising out of creating a dangerous situation:
R v Miller [1983] 2 AC 161
- Squatter smoking and his cigarette lit up the mattress, basically
created a fire.
However, an exception:
- R v Bowditch 2017
- Group of kids messing around, one falls in and drowns, the others
don’t even try to help
- Found guilty for gross negligence
Causation
- If deciding homicide must discuss causation,
- Part of actus reus
- Have to prove factual and legal causation
- Cause - the conduct caused the harm
4.1 Factual causation:
Factual causation is the principle that the defendant cannot be
considered the cause of an event if the event would have occurred in
precisely the same way without the defendant’s act or omission. In
other words, the Prosecution must prove that but for the defendant’s
act or omission the event would not have occurred - R v White [1910] 2
KB 124, guy poisoned his mom when she would have died from heart
attack anyways.
- Use the but for test, but for the defendants actions or omissions
would the outcome have happened?
- So if the outcome is not the same then satisfies the test
4.3 Legal causation’
There are a number of key principles involved in establishing legal
causation.
- Must walk through the applicable principles in the exam. Not
applicable ones can still be mentioned.
i. The consequence must be attributable to a culpable act
R v Dalloway (1847) 2 Cox 273 - the rider of a horse wasn’t holding the
reigns, when a girl run in front of him, he killed her
- The consequence can be blamed on the defendants culpable act
or omission.
- The prosecution must show this,
4.3.2 The culpable act must be more than a minimal cause of the
consequence
R v Pagett (1983) 76 Cr App R 279 - girl was used as a human shield
and was shot by the police.
- The defendant must have contributed significantly to the victim’s
death.
4.3.3 The culpable act need not be the sole cause
R v Benge (1865) 4 F&F 504 - train came onto the tracks while there
was some work being done, was part of the team.
- Could be one of the causes, doesn’t have to be the main one,
4.3.4 The accused must take their victim as they find them
For pre-existing medical conditions see R v Hayward (1908) 21 Cox
692
For mental conditions or religious beliefs see R v Blaue [1975] 1 WLR
1411.
- Egg-shell skull rule
4.3.5 The chain of causation must not be broken by an intervening
act
R v Pagett (above).
- The action of intervention is sometimes referred to by its Latin
name of ‘novus actus interveniens’ which translates to ‘a new and
intervening act’.
4.4 The two most common types of intervening act which may
potentially break the chain of causation
4.4.1 Medical intervention in homicide cases
R v Cheshire [1991] 3 All ER 670.
Even negligent medical treatment will not break the chain of causation
unless it is so independent of the accused’s actions and so potent in
causing death that it makes the contribution made by the accused’s
acts insignificant.
- The victim was shot,
- Negligent medical treatment breaks the chain of causation only if
so independent of D’s acts and so potent in causing death that
D’s contribution is insignificant.
- R v Jordan - the wound was nearly healed but was given
treatment that was allergic to and was continued despite the
ineffectiveness.
4.4.2 Intervention by a third party
R v Wallace [2018] EWCA Crim 690.
A defendant will not be liable if a third party’s intervening act is free,
deliberate and informed or their action was not reasonably foreseeable.
- Court of appeal said “would it be reasonably foreseeable that the
victim would seek out euthanise as a result of the defendant’s
actions or omissions?”
- Voluntary euthanasia would be enough to act as intervening act
- The jury found her not guilty of murder or manslaughter
R v Kennedy No2 [2007] UKHIL 38
- If the victim self- injected voluntary, the action was free, informed
and deliberate
- Therefore fellow addicts who assisted or the drug dealer a were
not held liable.
Monday, 19 January 2026 18:12
R v Wallace 2018:
The victim in this case was a Mark van Dongen, who was a Dutch
national, living and working in the Bristol area as an engineer. He and
the defendant, Berlinah Wallace, had been in a relationship which had
broken up. The victim had visited the defendant at her flat, at her
request and had ended up staying the night. Whilst he was asleep, the
defendant threw sulphuric acid on him with the words; “If I can’t have
you, no one else will”. His injuries were so horrific the jury was not
allowed to see photographs of him on his arrival at hospital or during
his treatment.
He had full thickness burns to 25% of his body, was in a coma for 4
months, lost the sight in one eye and most of the sight in the other, his
lower left leg had to be amputated and he was paralysed – at one
point, only being able to move his tongue. Mark was eventually
discharged to a care home, where he was found in a dreadful state by
his father, who organised a private ambulance to take him to a hospital
in Belgium.
After developing further complications, Mark applied for euthanasia,
which is legal in Belgium and his request was granted. He died on 2
January 2017.
The defendant was originally charged with an offence of applying a
corrosive substance with intent.
1. An offence is (allegedly) committed
2. A police investigation takes place (including arrest, detain,
interrogations)
3. The police and CPS decide whether to prosecute
4. The prosecution and defence begin preparing the case
5. The trial (if D is pleading not guilty)
6. Sentencing if D is convicted (or pleads guilty)
7. Appealing against sentence or conviction (or against the judge’s
ruling)
Criminal behaviour is established in accordance to societal values and
views at the time. Thus, it is changing, and evolving over time and what
is criminal is not always constant. Eg adulatory and homosexuality was
illegal before, whereas stalking and cyber fraud is recent.
Statutory offence - criminalised behaviour under statutes passed by
Parliament
Common law offence - criminalised behaviour under precedence, such
as murder
The burden and standard of proof
The legal burden of proof is on the Prosecution to prove all the
elements of the offence, including disproving the defence.
The standard of proof is beyond a reasonable doubt, so that the jury or
magistrates should convict only if they are sure of the defendant’s
guilt - Woolmington v DPP [1935] AC 462.
The evidential burden is also on the Prosecution to provide sufficient
evidence to show that the accused has a case to answer and to justify
a finding of guilt.
However, there are some (rare) instances where the defendant has
either the legal or the evidential burden of proving their defence.
Actus Reus
The actus reus elements of an offence are every element within the
definition of the offence which is not related to the state of mind of the
defendant – Nicola Monaghan Textbook on Criminal Law Directions 7th
edition (Oxford University Press).
- Guilty act or guilty omission, everything that makes up the crime
apart from the mental stuff, mens rea. Building block.
- Varies from offence to offence, find it in the statute or common
law
3.1 Some general principles
3.1.1 Voluntary conduct
Where the actus reus is defined so as to require conduct on the part of
the accused, the conduct must be voluntary if it is to be criminal.
3.1.2 State of affairs crimes
Some offences do not require any conduct at all and are defined so
that the actus reus is simply the existence of a state of affairs. Eg
crashing due to a bunch of bees.
For example, s.4(2) of the Road Traffic Act 1988 which makes it an
offence to be in charge of a motor vehicle on a road or other public
place while unfit to drive through drink or drugs.
3.2 Omissions - will only be charged if you had a duty to act but
failed
Although most offences are defined so that the actus reus is an action
or the existence of a state of affairs, in certain criminal offences the
definition of the actus reus is such that it may also be committed by
omission.
General rule
A defendant will only be criminally liable for an omission if the law
recognises that they were under a duty to act and they failed to do so.
Exceptions to the general rule - statutes or common law (duty
situations)
3.2.1 Some statutory offences:
- s.7 Road Traffic Act 1988 – failing to provide a specimen of
breath
- s.170(4) Road Traffic Act 1988 – failing to stop and report an
accident
3.2.2 Duty arising out of contract:
R v Pittwood (1902) 19 TLR 37
If you have a contractual duty to a person but you fail to do so, you
could file yourself liable,
- Left the gate open during lunch break and someone died
3.2.3 Duty arising out of relationship:
R v Gibbins and Proctor (1918) 13 Cr App R 134
- Eg, parent and child, spouses, based on aid,
The father of the child starved the kid, charged based on relationship
3.2.4 Duty arising out of assumption of care for another:
R v Instan [1893] 1 QB 450, R v Stone and Dobinson [1977] QB 354
- You made it your business, once you assume care for another
you establish a duty.
3.2.5 Duty arising out of creating a dangerous situation:
R v Miller [1983] 2 AC 161
- Squatter smoking and his cigarette lit up the mattress, basically
created a fire.
However, an exception:
- R v Bowditch 2017
- Group of kids messing around, one falls in and drowns, the others
don’t even try to help
- Found guilty for gross negligence
Causation
- If deciding homicide must discuss causation,
- Part of actus reus
- Have to prove factual and legal causation
- Cause - the conduct caused the harm
4.1 Factual causation:
Factual causation is the principle that the defendant cannot be
considered the cause of an event if the event would have occurred in
precisely the same way without the defendant’s act or omission. In
other words, the Prosecution must prove that but for the defendant’s
act or omission the event would not have occurred - R v White [1910] 2
KB 124, guy poisoned his mom when she would have died from heart
attack anyways.
- Use the but for test, but for the defendants actions or omissions
would the outcome have happened?
- So if the outcome is not the same then satisfies the test
4.3 Legal causation’
There are a number of key principles involved in establishing legal
causation.
- Must walk through the applicable principles in the exam. Not
applicable ones can still be mentioned.
i. The consequence must be attributable to a culpable act
R v Dalloway (1847) 2 Cox 273 - the rider of a horse wasn’t holding the
reigns, when a girl run in front of him, he killed her
- The consequence can be blamed on the defendants culpable act
or omission.
- The prosecution must show this,
4.3.2 The culpable act must be more than a minimal cause of the
consequence
R v Pagett (1983) 76 Cr App R 279 - girl was used as a human shield
and was shot by the police.
- The defendant must have contributed significantly to the victim’s
death.
4.3.3 The culpable act need not be the sole cause
R v Benge (1865) 4 F&F 504 - train came onto the tracks while there
was some work being done, was part of the team.
- Could be one of the causes, doesn’t have to be the main one,
4.3.4 The accused must take their victim as they find them
For pre-existing medical conditions see R v Hayward (1908) 21 Cox
692
For mental conditions or religious beliefs see R v Blaue [1975] 1 WLR
1411.
- Egg-shell skull rule
4.3.5 The chain of causation must not be broken by an intervening
act
R v Pagett (above).
- The action of intervention is sometimes referred to by its Latin
name of ‘novus actus interveniens’ which translates to ‘a new and
intervening act’.
4.4 The two most common types of intervening act which may
potentially break the chain of causation
4.4.1 Medical intervention in homicide cases
R v Cheshire [1991] 3 All ER 670.
Even negligent medical treatment will not break the chain of causation
unless it is so independent of the accused’s actions and so potent in
causing death that it makes the contribution made by the accused’s
acts insignificant.
- The victim was shot,
- Negligent medical treatment breaks the chain of causation only if
so independent of D’s acts and so potent in causing death that
D’s contribution is insignificant.
- R v Jordan - the wound was nearly healed but was given
treatment that was allergic to and was continued despite the
ineffectiveness.
4.4.2 Intervention by a third party
R v Wallace [2018] EWCA Crim 690.
A defendant will not be liable if a third party’s intervening act is free,
deliberate and informed or their action was not reasonably foreseeable.
- Court of appeal said “would it be reasonably foreseeable that the
victim would seek out euthanise as a result of the defendant’s
actions or omissions?”
- Voluntary euthanasia would be enough to act as intervening act
- The jury found her not guilty of murder or manslaughter
R v Kennedy No2 [2007] UKHIL 38
- If the victim self- injected voluntary, the action was free, informed
and deliberate
- Therefore fellow addicts who assisted or the drug dealer a were
not held liable.
