Police have increased the number of searches around the climate camp near Hoo in Kent, leading to criticisms from two MPs and an MEP that the operation is undermining civil liberties.
Kent Assistant Chief Constable Gary Beautridge said the extension of police powers to stop and search anyone near the Climate Camp was to protect residents, police and protesters.
Within the boundaries of the site, the camp appears to be peaceful with tents arranged in 'regions' determined by which part of the UK the campers have come from.
The activists are opposing plans for a coal-fired power station near Hoo. Energy company E.ON UK has said the coal-fired unit will be 20% cleaner than the current plant.
The camp is run on renewable energy, with recycled wood-burning stoves for cooking, solar and wind power for the media centre and cinema, and pedal power for the camp radio station.
Environmentally friendly toilets, washing facilities and drainage have been set up by the campers to minimise waste and avoid causing damage to the site.
Throughout the week a programme of workshops and seminars on subjects as varied as bike maintenance and poetry have been held in marquees and tents.
Campaigners have also been preparing for a parade on Saturday's day of action, when they say they hope to close down the Kingsnorth power station.
Activists have set up structures which they say are legally classed as premises while occupied and cannot be moved from the Climate Camp site which is occupied by about 1,500 people.
Outside the camp boundaries the police are searching visitors entering and leaving the site, including local residents, members of the clergy and the press.
Several people were arrested on Friday after apparently objecting to officers searching them. Several officers held down this young woman before they took her away in a van.