It was no ordinary break-in. On June 20, under the cover of darkness, two activists entered what should have been one of Britain’s most secure military bases, RAF Brize Norton, and vandalised two Voyager planes.

The co-founder of a pro-Palestinian campaign group sought on Monday to challenge the British government's decision to ban the group under anti-terrorism laws, a move her lawyers said had "the hallmarks of an authoritarian and blatant abuse of power".