The streets of Windsor, home to the royal family's Windsor Castle in the south of England, are filled with hundreds of Extinction Rebellion protesters marching under the watchful eye of the police. "We are here today delivering letters to the king," explains Marijn van de Geer. Grandparents and children have written "to tell them about their concern about climate and ecological breakdown, as well as our failing political system," she adds. Protesters have set up camp in Windsor's Home Park for a weekend of peaceful action. IMAGES AND SOUNDBITES