After a tense hour stuck on the M4, the traffic gods smiled and we arrived at the Ai Weiwei exhibition at the Royal Academy spot on time, writes Wayne Spilsbury.

The social and political commentary woven into the work of the famous Chinese dissident was often subtle and sometimes more obvious. Students came to understand the context of sculptures made from destroyed Buddhist temples as well as the pieces using remnants of shoddily built buildings which collapsed in the 2008 Sichuan earthquakes in China killing so many school children.

This contrasted markedly with the Barbara Hepworth retrospective at Tate Britain. The exhibition traces her gradual development through figurative carvings through to pierced abstract forms in a number of media. The two exhibitions highlight the ways in which concept, medium and techniques can be used in many ways to create art works which move us in different ways.