Image: Queen Elizabeth II and then Indian Prime Minister Pandit Nehru review Cadet Corps in January 1961. Photograph: Keystone-France/Gamma-Keystone/Getty Images
Image: Photograph taken on January 26, 1961: From left to right; Prince Philip (extreme left) with Prince Jagat-Singh (with his foot on tiger's head), the Maharajah of Jaipur, Queen Elizabeth II and the Maharanee of Jaipur. The tiger which was over 8ft long was shot by Prince Philip during a tiger hunt during the Royal Tour of India. The skin was sent to Windsor Castle. Photograph: Fox Photos/Getty Images
Image: Queen Elizabeth II and President Rajendra Prasad watching Prince Philip Playing Polo on February 1, 1961. Photograph: Keystone-France/Gamma-Keystone via Getty Images
Image: Queen Elizabeth II perched in a howdah on the back of an elephant at Benares, during her tour of India, January 25, 1961. Photograph: Hulton Archive/Getty Images
Image: Queen Elizabeth II and Prince Philip, Duke of Edinburgh visiting the seventeenth-century Taj Mahal during their six-week royal visit to India, January 29, 1961. Photograph: Hulton Archive/Getty Images
Image: Queen Elizabeth II at a model village in Jaipur, during a royal tour, January 22, 1961. Photograph: Derek Berwin/Fox Photos/Hulton Archive/Getty Images
Image: Queen Elizabeth II presents the Order of Merit to Mother Teresa at the Presidential Palace on November 24, 1983 in Delhi, November 24, 1983. Photograph: John Shelley Collection/Avalon/Getty Images
Image: Queen Elizabeth II in a traditional Indian 'Palki' during a visit to India on November 17, 1983. Photograph: Tim Graham Photo Library via Getty Images
Image: Queen Elizabeth II and Prince Philip visited a cottage industries emporium, Delhi, India, January 28, 1961. Photograph: Fox Photos/Hulton Archive/Getty Images
Image: Queen Elizabeth II meets Prime Minister Narendra Modi at Buckingham Palace on the second day of his visit to the United Kingdom on November 13, 2015, in London, England. Photograph: Dominic Lipinski/WPA Pool/Getty Images