Agent Provocateur

No, not the lingerie company. Rather the infiltration of civic groups (typically radical or interested in progressive causes) by police or other security organizations in order to incite violent or illegal actions. Like Mark Kennedy, recently outed in Britain as having spent years undercover in the UK environmental movement. And now the Guardian is reporting on three major energy firms that have employed private security firms to carry out covert intelligence-gathering operations on environmental activists and groups.
Governments in the UK have viewed environmental protest as potentially violent terrorism since at least the rule of Margret Thatcher. Infiltration with agent provocateurs in the US environmental movement go back to the monkeywrenchers of the 80s and even earlier (Nixon's enemy list shows that paranoia has long been a feature of the ruling class south of the border). In Canada, RCMP agent provocateurs were responsible for much of the paranoia around the French-Canadian separatist movement in the 1970s.
George Monbiot reports that he could not find "a single proven instance of a planned attempt in the UK to harm people in the cause of defending the environment". This jibes with reports from the mid-1980s here in the Pacific Northwest when a tremendous panic was being whipped up against "tree spiking," where large nails, it was claimed, were being pounded into trees in order to damage mill machinery. Despite the hysteria whipped up by the local media and public pronouncements from various logging companies, only one incident of possible tree spiking was reported when, in 1987, California mill worker George Alexander was seriously injured when the bandsaw he was operating was shattered by either an old nail or a tree spike. One unproven case of possible spiking became the basis for tree spiking being declared a federal felony in the United States in 1988.
The agent provocateur is an excellent tactic for keeping track of a group while simultaneously discrediting it. Which, of course is why it's used. But there are some actions that such agents really cannot guard against. Like the new Greenpeace ad.