Tate Modern’s Turbine Hall daubed with graffiti.

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.