LONDON, UNITED KINGDOM - NOVEMBER 01: British Prime Minister Theresa May, shoe detail, takes part in a ceremonial welcome for Colombia's President Juan Manuel Santos and his wife Maria Clemencia de Santos at Horse Guards Parade on November 1, 2016 in London, England. The President is on a state visit to Britain. (Photo by Gareth Fuller - WPA Pool/Getty Images)

LONDON, UNITED KINGDOM - NOVEMBER 01: British Prime Minister Theresa May, shoe detail, takes part in a ceremonial welcome for Colombia's President Juan Manuel Santos and his wife Maria Clemencia de Santos at Horse Guards Parade on November 1, 2016 in London, England. The President is on a state visit to Britain. (Photo by Gareth Fuller - WPA Pool/Getty Images)