Twelve posters commissioned to mark the London 2012 Olympics and Paralympics have been unveiled at the Tate Britain.

Bridget Riley Ė Rose Rose and Howard Hodgkin - Swimming Photo: LONDON2012

Gary Hume - Capital and Martin Creed - Work No. 1273 Photo: LONDON 2012

Sarah Morris - Big Ben 2012 and Fiona Banner - Superhuman Nude Photo: LONDON 2012

Anthea Hamilton - Divers and Tracey Emin - Birds 2012 Photo: LONDON 2012