Britain's Trident nuclear missile programme has long been politically controversial. In 1999, the controversy entered the judicial arena in Scotland, in two cases involving ‘direct action’ against Trident installations by anti-nuclear activists. In both cases, the actions were intended not as protests against Britain's nuclear-weapons policy, but rather as actual operations to disable the weapons themselves. The acts were, in other words, in the nature of acts of sabotage. Both incidents led to criminal prosecutions. In both cases, the accused parties sought to use international law as a defence. In both cases, the Appeal Court of the High Court of Justiciary—the highest court for criminal cases in Scotland—rejected the defence. In the process, however, the Appeal Court had occasion to expound upon some controversial points regarding nuclear weapons. Each of these cases will be discussed in turn.