The UK government is moving to ban the activist group Palestine Action, classifying it as a terrorist organization under a controversial new measure. Home Secretary Yvette Cooper announced on Monday that the group’s history of “unacceptable criminal damage” has finally reached the threshold for such a designation.

A parliamentary order, slated for June 30th, will criminalize membership in or support of Palestine Action. This means individuals could face prosecution for affiliation with or even public endorsement of the group. The decision follows a recent incident at RAF Brize Norton, Britain’s largest air base, where two Palestine Action activists allegedly sprayed Voyager aircraft with red paint.

Cooper described the RAF Brize Norton incident as a “disgraceful attack,” an event currently under investigation by the Counter Terrorism Policing network. The move to ban Palestine Action is certain to spark heated debate and raise questions about the scope of terrorism legislation in the UK, and its application to political activism.