International film actress Gillian Anderson pictured on the rooftop of the Ritz-Carlton Hotel overlooking Red Square in a British Airways Business Class seat to launch the British Airways long haul service on the London – Moscow route on March 6, 2012 in Moscow, Russia. (Photo by Gareth Cattermole/Getty Images For British Airways)

Emergency services work at the scene of a bus accident on the Kingsway in central London February 2, 2015. A number 91 double-decker bus had its roof ripped off after hitting a tree, causing injury to passengers and passers-by, local media reported. (Photo by Peter Nicholls/Reuters)

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)

Models walk the runway at the “A Child of the Jago” fashion show during London Fashion Week at the Wilton Music Hall on September 21, 2011 in London, United Kingdom. (Photo by Ian Gavan/Getty Images)

Fireworks light up the London skyline and Big Ben just after midnight on January 1, 2012 in London, England. Thousands of people lined the banks of the River Thames in central London to see in the New Year with a spectacular fireworks display. (Photo by Peter Macdiarmid/Getty Images)

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)