Rihanna arrives for the Stella McCartney Special Presentation at 13 North Audley Street during London Fashion Week Autumn/Winter 2012 on February 18, 2012 in London, England. (Photo by Samir Hussein/Getty Images)

Bradley Hemmings and Jenny Sealey MBE pose for the camera with a Giant Iron Man on the set of Iron Man at the Greenwich and Docklands Festival in St Alfege Park on June 24, 2011 in London, England after they are announced by LOCOG as the Artistic Directors for the Paralympic Games Opening Ceremony. (Photo by Christopher Lee/Getty Images)

A model walks the runway during the Craig Lawrence show at London Fashion Week Autumn/Winter 2012 at Somerset House on February 19, 2012 in London, England. (Photo by Stuart Wilson/Getty Images)

A simulated casualty is evacuated during an emergency services exercise at the disused Aldwych underground station on February 22, 2012 in London, England. Operation Forward Defensive aims to test the response to a terrorist incident on the London Underground network during the 2012 Olympic Games. (Photo by Peter Macdiarmid/Getty Images)

Paint splattered police officers look on during clashes outside Top Shop on Oxford Street, during marches in protest at government cuts on March 26, 2011 in London, England. Thousands are taking part in the Trades Union Congress (TUC) organised march to Hyde Park where a rally will take place. Police say they are deploying 4500 officers. (Photo by Dan Kitwood/Getty Images)

Dancers at the Windmill Theatre in London, England practice a routine wearing gas masks and hard-hats with their costumes, 1940. (Photo by Hulton Archive/Getty Images)

Londoners sleep on the platform and on the train tracks at Aldwych Underground station,London, during heavy all night Nazi bombing raids, October 8, 1940. (Photo by AP Photo)

Following a large air raid by German bombers, local people, coming out of their air raid shelters found a bus standing on end in a large crater, in Balham, London, October 15, 1940. (Photo by AP Photo)