Insanity AO1

What type of defence is ‘insanity’ and where does it come from?

A common law defence from M’Naghten 1843

How may D prove they’re not sane?

Everyone is presumed sane- D has the burden of proof to prove they are not

(I.e balance of probabilities)

What must D suffer from?

A defect of reason

What did Clarke say about a defect of reason?

It must be a complete loss of power of reasoning (forgetfulness is not enough)

Where must the defect come from?

A disease of the mind

What may ‘disease of the mind’ include?

Physical conditions which may affect the mind-Kemp

What did Hennessey set out?

A diabetic high blood sugar episode- allowed the defence

What MUST the offence be induced by?

Disease of the mind OR an internal factor

• Burgess-sleepwalking

• Sullivan-epilepsy

Will D have had any intent?

No- D doesn’t know the nature/quality of their act (eg if unconscious or if they didn’t know the act was wrong)

What did Windle define ‘wrong’ as?

Legally wrong (against the law)