You will only be able to raise the defence of honest and reasonable mistake of fact in relation to ‘strict liability’ offences.
Strict liability offences are offences which do not require proof that you intended to commit the crime – for example, speeding.
The defence of honest and reasonable mistake of fact can be raised where you honestly believed that you were acting lawfully when you committed the offence, and that you would not have acted in that way if you knew that what you were doing was against the law.
In order to successfully raise the defence of honest and reasonable mistake of fact, you must present evidence to prove on the balance of probabilities (that is, more than 50%) that:
1. The mistaken belief was held honestly
You must be able to prove that you honestly and genuinely held the belief. For example, if you were charged with driving while disqualified but you were not aware that you were disqualified because the RMS had informed you that you still held a valid license.
2. The belief was ‘reasonable’
Whether or not your belief was ‘reasonable’ will be judged according to whether an ordinary person in your circumstances would have held the belief. The court will consider any steps that you took to ascertain your belief – for example, where you’ve been charged with a sexual offence, the court will consider any steps that you took to clarify if consent was given.
3. The belief related to a particular fact, rather than the law
The belief must be about the facts related to the offence – you will not be able to simply argue that you were not aware that what you were doing was illegal.
You must also prove that if the facts were true (as you believed), you would not be committing an offence.
For example, where you are charged with a drug offence, but you mistakenly believed that the drug was something else that was legal – for example, where you were given a marijuana plant and informed that it was some other legal plant.
If the defence is raised successfully, you will be found ‘not guilty’ of the strict liability offence.