British protesters won a High Court challenge on Tuesday that public order laws cannot be used against campaigners who damage or destroy genetically modified (GM) crops. London's High Court ruled that the laws could not be used when no people are present in the crop fields during the protesters' activities. Protesters and the Crown Prosecution Service had both challenged conflicting decisions over the issue by lower courts in different parts of the country. Rowan Tilly, 43, from Brighton, and the other campaigners were charged in two separate cases with causing criminal damage to GM crops under the 1994 Criminal Justice and Public Order Act. A court in Cambridge found the protesters guilty, but Weymouth magistrates acquitted them. Clarifying the law Justice Anne Rafferty said the protesters could not be convicted in either case because the law required that other people had to be engaged in a "lawful activity" on the land for there to be an offence. "The Act was aimed at preventing intimidation and disruption of those engaged in lawful activity," she said. No-one was working on the land during either of the crop raids involving Tilly. The Director of Public Prosecutions is considering appealing against the ruling to the House of Lords.