On Monday evening, as celebrations for 20 years of BP 'support' for British Art got underway with a Summer Party at Tate Britain, Liberate Tate disrupted the proceedings inside and out by pouring hundreds of litres of 'oil'(molasses) and scattering thousands of feathers in an 'art performance'. The action follows last month's disruption of Tate Modern's 10th Birthday celebrations, which involved hanging dead fish and birds from dozens of giant black helium balloons.
The Tate Summer Party had been planned to be in the museum gardens and involve speeches from BP executives. However, due to the rumours of disruption, Tate was forced to hold the entire event inside the museum and no speeches were made.
Liberate Tate is a network founded during a workshop in January 2010 on art and activism, commissioned by Tate. When Tate curators tried to censor the workshop from making interventions against Tate sponsors, the incensed participants decided to continue their work together beyond the workshop.
See also this from Harpymarx