The document provides information and discussion questions about the defense of diminished responsibility in English criminal law. There are four key elements to the defense that must be proven: 1) abnormality of mental functioning, 2) recognized medical condition causing the abnormality, 3) substantial impairment, and 4) the abnormality must provide an explanation for the killing. The document examines cases that have helped define these elements and discusses debates around topics like the burden of proof, the role of intoxication, and proposed reforms to the defense. Students are prompted to consider application of the law to hypothetical scenarios and to critically analyze statements related to diminished responsibility.

1. Checking your Knowledge:
Can you complete the gaps?

2. Voluntary Manslaughter:
Diminished Responsibility
Offences against the Person 1:
MAH 2013-14

3. The Basics of pleading DR…
Why do we need it?
Cause the law on insanity and
automatism is nuts! And the
mandatory life sentence isn’t far
behind.
Windle 1952
Why wouldn’t you
want to plead it?
Moyle 2008
Why is insanity not
enough?
A Grade Challenge:
Why was Erskine
not keen on
pleading
diminished
responsibility?

4. Proof and getting before
the jury...
You argue it, but only if the
reasonable jury would think you’ve
got a case!
Sutcliffe 1981
What might influence a
judge to withdraw it?
 Jury decide this as it is a matter of fact
Are juries the best people to decide
matters of medical knowledge?
 Burden of Proof is not against art. 6
Foye
The Basics of pleading DR…

5. Old or New?
All of you should be able to identify the key elements of the two offences.
Most of you should be able to consider what impact one of those changes has had on
the operation of the law.

6. Element One:
Abnormality of Mental Functioning
R v Byrne (1960)
“ state of mind so different from that of
an ordinary human being that the
reasonable man would term it abnormal.”
“The mind’s activities in all its aspects”
Thinking,
Why do some people argue that the
inclusion of ‘irresistible impulse’ unfair
to most defendants?

7. Starter:
Can you spot the problems with this summary?
Diminished responsibility is a complete defence, which D may only argue to murder. It has most
recently been reformed in the Coroners and Justice Act 1957, which updated and clarified the law.
D must prove the defence beyond all reasonable doubt, and must advance medical evidence to
support his argument. The majority of DR cases end up before a jury, who have to judge the
sanity of a defendant.
There are three elements to the defence, which need to be proven. Firstly, was D suffering from
an abnormality of mind, which is defined in Burn as a state of mind so different from the ordinary
that it is abnormal’. In addition, this must be caused by a recognised medical condition.
The final two elements require D to be substantially impaired within the wording of the act, and
for his abnormality to have been the cause of the killing. This last decision has been welcomed by
doctors.

8. Starter:
Can you spot the problems with this summary?
Diminished responsibility is a complete defence, which D may only argue to murder. It has most
recently been reformed in the Coroners and Justice Act 1957, which updated and clarified the law.
D must prove the defence beyond all reasonable doubt, and must advance medical evidence to
support his argument. The majority of DR cases end up before a jury, who have to judge the
sanity of a defendant.
There are three elements to the defence, which need to be proven. Firstly, was D suffering from
an abnormality of mind, which is defined in Burn as a state of mind so different from the ordinary
that it is abnormal’. In addition, this must be caused by a recognised medical condition.
The final two elements require D to be substantially impaired within the wording of the act, and
for his abnormality to have been the cause of the killing. This last decision has been welcomed by
doctors.

9. Starter:
Can you spot the problems with this summary?
Diminished responsibility is a partial defence, which D may only argue to murder. It has most
recently been reformed in the Coroners and Justice Act 2009, which updated and clarified the law.
D must prove the defence on balance of probabilities, and must advance medical evidence to
support his argument. The majority of DR cases do not end up before a jury, who have to judge
the sanity of a defendant.
There are four elements to the defence, which need to be proven. Firstly, was D suffering from an
abnormality of mental functioning, which is defined in Byrne as ‘a state of mind so different from
the ordinary that it is abnormal’. In addition, this must be caused by a recognised medical
condition.
The final two elements require D to be substantially impaired within the wording of the act, and
for his abnormality to have been a cause of the killing. This last decision has been welcomed by
doctors.

10. Element Two:
Recognised Medical Condition
Thinking:
Mr Higginbotham
Has the law lost its merciful origins or
was DR in its older form simply
misused to fill in other gaps in the
law?
Psychopathy
Paranoia
Epilepsy Depression
Battered Women’s
Syndrome
Asperger’s syndromePostnatal Depression
Pre-menstral tension

11. Element Three:
“Substantially Impaired”
Lloyd 1967
The word 'substantial' in the 1957 Act did not mean total, nor did it mean trivial or
minimal. It was something in between and Parliament had left it to juries to decide on
the evidence. Most recently confirmed by GOLDS 2014
Confirmed by
Brown 2011
In the Act, it actually specifies what is meant by this, and D may argue any of these.
Understand the nature of their conduct
The ability to form rational judgement
The ability to exercise control
What do you think is meant by each of
these? Illustrate each one with a case!

12. Student task:
To show your
understanding,
answer the two
questions, using
supporting cases to
explain your
conclusions!
Element Four:
D’s abnormality must provide an explanation for
the killing
“significant causal factor”
 Explains why diminished responsibility mitigates
liability for murder (the reason it’s an excuse!)
 Emphasises that it must be active at the time of
the killing (remember Campbell?)
...but it really doesn’t fit with modern medicine and
psychiatric notions of explanation:
Can you just blame the condition
for the reactions of the defendant?

13. There are two occasions that we need to consider...
A recognised medical condition problem:
Alcohol & Drugs (Intoxication)
D is intoxicated and suffers from an
unrelated AoMF
D’s AoMF is caused by the
intoxication
Gittens
Egan
Despite the drink
was D sufficiently
impaired
If sober would he
have been impaired
Now a problem...
So, let’s see if the House of Lords can
solve this...

14. Homework:
Case revision!
Learn em. You will have a short test on them
next Thursday. 
1. Byrne
2. Ahluwalia
3. Lloyd
4. Brown
5. Dietschmann
6. Seers
7. Campbell
8. Reynolds
9. Smith
10. Bradley

15. Key Case:
R v Dietschmann
1. What are the facts of the case?
2. On what grounds was D arguing
diminished responsibility?
3. What is the general rule on intoxication
and diminished responsibility?
4. When can drink give rise to a s.2 Homicide
Act 1957 defence?
5. What is the ratio of the case?
6. Does s.2 require the abnormality of mind
to be the sole cause of D’s acts in killing?
7. What is the question to be put to the jury
when assessing whether the impairment is
sufficient?
8. Which case did they follow: Egan or
Gittens? Why?

16. And now for the other issue...
D is intoxicated and suffers from an
unrelated AoMF
D’s AoMF is caused by the
intoxication
Situation One: Voluntary Acute Intoxication
Thinking:
1. What issues do you think
influenced this decision?
2. What does this case illustrate
about the courts’ use of DSM and
the World Health manuals in
determining ‘abnormalities of
mental functioning’

17. And now for the other issue...
Tandy
Wood
...confirmed in Stewart
Must cause brain damage or
irresistible impulse to drink.
The clear lines drawn in Tandy
are no longer appropriate. It is
the overall syndrome, not the
nature of one drink as
voluntary.
D is intoxicated and suffers from an
unrelated AoMF
D’s AoMF is caused by the
intoxication
Situation Two: Alcohol Dependency Syndrome
The response of the Court to the situation in
Tandy is too strict and goes against the idea
that diminished responsibility is a measure of
compassion: really?

18. Consolidation and Development:
“The courts approach to the problem of the intoxicated,
mentally disordered offender, is muddled and unclear.”
All of you need to decide whether the
statement is true or false and why
Most of you need to support your
argument with reference to at least two
supporting cases
Some of you will address both issues
surrounding intoxication and consider
the consistency across the decisions.

19. Developing Your AO2:
How accurate are these statements?
1. It should be a mitigating factor in sentencing instead (the Spencer/Lloyd Amendment)
2. The new version brings the law into line with medical knowledge.
3. It is imposing an unfair burden of proof on the defence
4. It classes those in abusive relationships as “abnormal” in some way.
5. The new defence provides a much more strict approach to the interpretation of ‘abnormality of
mental functioning’ and doesn’t allow the same flexibility as the old law. R v Higginbotham (2004)
6. It is almost impossible to separate intoxication and inherent causes.
7. The use of the defence can involve a range of overly complex and legal terminology which can be
difficult for a jury to understand.
8. The Coroners and Justice Act 2009 is only a halfway effective reform. The government only
included it because they wanted to reform provocation.
Pass Grade: Clear explanation
C Grade: Supported by well explained and criticised case
B Grade: Counter argument introduced and explained.
A Grade: Counter argument discussed and illustrated.

20. AO2 Reform:
What else could we do?
Draft Criminal Code:
“such mental abnormality as would
be substantial enough to reduce the
charge... to manslaughter.”
Burden of Proof?
“Developmental immaturity”*
No mandatory life
sentence?
*you can also use your homework notes to add to these.
Spencer/Lloyd
Amendment

21. Application:
Can you apply the law to determine D’s liability for
the death(s)
Simon deliberately kills 6 women, claiming he was driven by God to rid the
world of prostitutes (although 3 of his victims were not prostitutes). Medical
experts all agree that he is a paranoid schizophrenic.
Bob, who was suffering from depression and an alcoholic, stabbed his brother
Jim to death after drinking ½ bottle of whiskey. Bob had just been prescribed
medication for the depression and thought that his brother had been stealing
them and replacing them with sugar pills. He usually drank vodka, but had
none in the house.

22. Plenary:

23. Starter:
What’s the case?
Can you identify the facts or the name of the case?
Can you identify the area
the case applies to?
1. My mind is burning with one desire...
2. I told you I’d do it!
3. Not a perfect plan to reach France...
4. He was a bit too eager to break in
(hic!)
5. Depression isn’t everything (not
when it comes to manslaughter!)
6. They really were coming to get me!
7. The baby made me do it.
8. Aunt you sad? You should watch out!
9. Precedent can be deadly.
10. Breakfast’ll kill you (36 hours later)

24. 20 marks (one grade!)
All AO2
Definitions are key!
Address each
statement separately
No cases or statutes
Use bullet points and
names!
Conclude clearly, using
the key words of the
question.
Section C Question:
Applying your knowledge

25. Statement C: Jim is still responsible for
the death of Louis despite Sebastian’s
actions.
Statement B: Jim can still plead diminished responsibility to the
death of Louis despite the alcohol as he was still substantially
impaired.
Statement A: Jim cannot plead diminished responsibility over
Louis’ death as he was suffering from an abnormality of mental
functioning.
Jim, who is on medication for an adjustment
disorder, drinks half a bottle of vodka with his
friend, Louis. Jim, thinking that Louis has stolen
his vodka, attacks him with a claw hammer,
causing him serious injuries. Sebastian, the
paramedic comes to help, but accidently breaks
Louis’ rib, puncturing his heart. Louis is put onto
a life support machine which is switched off by
Steven, who is trying to save the hospital
money.
Statement D: Steven is not
responsible for Louis’ death as he has
only switched off the life support
machine.
 Steven would be responsible for the death of Louis if he had
intended the death and caused the death without breaking the
chain of causation.
 As he has flipped the switch, his actions have clearly been an
operative and substantive cause of Louis’ death, which would
be enough for the actus reus of murder.
 In addition, by choosing to flip the switch, it is clear that his
‘true desire’ to cause the death.
 He is not acting in the best interest of the patient, and nor
does Louis appear to be brainstem dead.
 Therefore the statement would be false as although Jim
stabbed Louis, Steven’s actions still legally cause the death.

26. Statement C: Sam would not be
able to argue diminished
responsibility as he was not
substantially impaired at the time
of the death
Statement B: Sam would not be able to argue
diminished responsibility as he was not suffering from
an abnormality of mental functioning
Statement A: Sam would be liable for the murder of
Susie as he intends to cause her serious harm.
Sam has recently been feeling very down
as his girlfriend Susie has left him. He has
been to the doctor, who has put him on
medication to help. One night Sam
meets his friend Mike for drinks, and
over the course of a couple of hours,
consumes a large quantity of alcohol. On
the way home, he breaks into Susie’s
house and strangles her.
Statement D: Sam would be able
to argue diminished responsibility
as he was intoxicated at the time
of Susie’s death.
Demonstrate all those lovely
practised skills...

27. Plenary:
Answer one of these questions
E
A
B
C
D
Examine the issues with the defence raised by the
case of Brown.
Why is the case of Byrne important to the law on
diminished responsibility?
Identify two conditions which may be enough for a
pleading of DR under the law and illustrate them with a
case
Explain why we allow some defendants to plead
diminished responsibility
What is meant by voluntary manslaughter?