G20 Summit: World leaders pose for photocall at Buckingham Palace

G20 Summit: World leaders pose for photocall at Buckingham Palace; Barack Obama (US President) bowing as greeting Prince Saud al-Faisal / General view world leaders chatting as waiting for photocall / Dmitri Medvedev (Russian President) shown his seat / More of leaders chatting / Queen Elizabeth entering room then along to her seat for photocall / G20 and world leaders taking seats for photocall / Obama shaking hands with Medvedev as along to take his place in line-up / Obama standing next to Kgalema Motlanthe (South African President ) / Hu Jintao (Chinese President), Brown, Queen Elizabeth and Lula da Silva smiling as posing for photocall / World leaders posing for photocall / Leaders standing up (some applauding) / Silvio Berlusconi (not seen) saying 'Mr Obama' in loud voice SOT / Elizabeth getting up and looking round as saying 'What is it?' (indistinct) / Brown and Jintao speaking to Elizabeth (not heard) / de Kirchner greeting Lee Myung-Bak (South Korean President)