Activists occupied the Tate Modern’s Turbine Hall overnight on Saturday in protest at the gallery’s sponsorship by oil company BP. The 75 demonstrators from the Liberate Tate group, dressed in black with veils covering their faces, spent 25 hours scrawling words of warning about climate change in charcoal on the sloping floor of the hall. They refused to leave the building when it closed and were eventually allowed to stay overnight. They left at lunchtime on Sunday