The Chinese artist and dissident Ai Weiwei is in London for a major retrospective of his work at the Royal Academy of Arts.

Ai Weiwei had initially been refused a six-month visa by the British government and was not expected to attend.

The exhibition looks at the last 20 years of his work, including political pieces relating to his time under arrest in China and to the 2008 Sichuan earthquake.

Ai Weiwei gave the BBC's Will Gompertz a guided tour of the exhibition.

The Ai Weiwei exhibition is at the Royal Academy in London from 19 September until 13 December 2015.