Artists from activist group Liberate Tate stage a performance in Tate Britain on the anniversary of the Deepwater Horizon explosion that killed 11 workers and released 4.9 million barrels of oil into the Gulf of Mexico. A naked member of the group has had an oil-like substance poured over him by silent figures dressed in black and wearing veils, and is now lying in a fetal position on the floor in the middle of the exhibition Single Form. Dedicated to the human body, Single Form is one of a series of âBP British Art Displaysâ staged throughout the galleries of Tate Britain.