From Westlaw:
D was convicted of riotous behaviour and incitement to riotous behaviour in Londonderry by exhorting people to keep the police out of an area by violence and throwing a stone at the police herself. The defence was one of justification, it being submitted that D honestly and reasonably believed that the police were about to behave unlawfully. On appeal, held, that such a belief did not afford D a defence in that (1) D and the persons incited had a common purpose to exclude the police by force; (2) the danger which D was alleged to have anticipated was not sufficiently specific or imminent to justify her actions; (3) the force used by D was so excessive as to be unwarrantable; (4) as regards incitement, there was no evidence to show that those incited by D to riot were actuated by an honest and reasonable apprehension of unlawful violence by the police and her incitements were therefore directed to encourage others to do what for them was prima facie unlawful; (5) the right to do otherwise unlawful acts could not justify action against a lawfully constituted constabulary while acting as such in the exercise of its proper functions; (6) there was no sufficient relationship between D and the people incited, to justify her acting in their defence; (7) the common law duty imposed on all citizens to help in suppressing riots and to assist the constabulary, made it impossible for D to justify her conduct in encouraging rioters.