Honest and reasonable mistake of fact applies is a defence available to offences where the prosecution is not required to prove that an accused intended to commit the crime in order to make out a case (strict liability offences).
An honest and reasonable mistake of fact occurs where an Accused person has committed an offence labouring under an honest belief that is reasonable but mistaken and as a consequence of that mistake commits a criminal offence.
The rationale behind the defence is that if the honest and reasonable mistake of fact as to the circumstances actually existed, then no criminal offence was committed. As such, the Accused person is not liable for their offending. A common example of when honest and reasonable mistake of fact is raised is in circumstances where someone was unaware that they were suspended from driving and as a consequence drove whilst suspended.
In order to raise honest and reasonable mistake of fact an Accused person must put forward some evidence that the defence, but once raised, the onus lies on the prosecution to prove that no such belief was held by the defendant.