I would like to provide the committee with a little bit of context that may be of use with regard to the provisions on self-defence, which actually were amended by Parliament just a few years ago. It's the one defence, actually, at present, that can be invoked when a person is charged with murder.
It speaks of a person having a reasonable perception that they are being assaulted or threatened. In other words, mistakes in terms of the application of self-defence or the use of force in self-defence, even killing a person in self-defence, will only be available if those mistakes were reasonable in the circumstances.
Just to have a little bit of context, in common law, it's the courts that told us that, when interpreting the old self-defence provisions in the context of exculpatory claims, mistakes should be reasonable ones. In the context of interpreting an offence itself—so where an offence includes a mental element—a mistake that's unreasonable would still negate the mental element for the crime and result in the person not being convicted. But where it's an exculpatory claim, which is really society's way of saying this was criminal, but not notwithstanding that it was criminal, we wish to give you an excuse so you won't be convicted. The courts have, on the whole, tended to say—and this is what's reflected in the self-defence provisions—that mistakes must be reasonable ones.