Demonstrators who breached the fences of Britain's Atomic Weapons Establishment (AWE) in Burghfield early on Sunday morning described "invisible" state repression after police threatened them with arrest unless they surrendered their personal details.
The site, which surrounds a warhead manufacturing plant and is owned by the Ministry of Defence, is now also home to a "disarmament camp" erected by Action AWE and Trident Ploughshares.
Campaigner Angie Zelter told the Morning Star today that people were welcome to join the camp's 30-odd residents for a fortnight of direct actions against Britain's nuclear weapons programme.
But police working for the Ministry of Defence had already threatened the camp's occupants with arrest unless they surrendered their names and addresses, in order to charge them with camping in a controlled area.
"It's not true - peaceful protest is legal, even on Ministry of Defence property," she said.
"Are they really going to waste court time with dozens of cases on camping bylaws, which they will almost certainly lose?"
In 2009 a Supreme Court ruling quashed a similar case against a camp at AWE Aldermaston, finding that enforcement of the bylaws had breached the activists' rights to freedom of expression and freedom of assembly.
Ms Zelter said the ruling was common knowledge.
"Basically it's a way of getting information and charging people without a whole lot of arrests."