The Buck stopped here

The Buck stopped here is a weekly blog by our contemporary art correspondent Louisa Buck covering the hottest events and must-see exhibitions in London and beyond

Activist art steps in when words are not enough

Fiona Banner drops a klanger outside Defra while Laure Prouvost takes language to new levels

Halloween with Ai Weiwei: artist's new film screens in Piccadilly Circus and online tonight

The Chinese dissident artist is stopping the regular advertisements in the famous square for an hour