Ai Weiwei - Without Fear or Favour

Architect, photographer, curator and blogger, Ai Weiwei is China's most famous and politically outspoken contemporary artist. As Ai Weiwei's latest work is unveiled in the Turbine Hall at Tate Modern, Alan Yentob reveals how this most courageous and determined of artists continues to fight for artistic freedom of expression while living under the restrictive shadows of authoritarian rule.