Jill hears a voice even when no-one is talking to her. The voice in her head tells her she has been a bad girl and will be punished severely.

Jill tells her voice she is very sorry and does not want to be punished.

Her voice tells her someone must be punished for her badness.

Jill beats her younger sister with a cricket bat handle till he is unconscious.

As a result Jill is arrested and charged.

At the police station, Jill tells the police she had 'to obey the voice', the voice gives her 'no other choice'. There's 'never any other choice'.

Can Jill use the excuse of insanity as a defence?