FILE - In this Dec. 16, 1984 file photo, Mikhail S. Gorbachev poses with Britain's Prime Minister Margaret Thatcher at the prime minister's official country residence in Chequers, north of London. In the scripted world of high-profile diplomacy, every move is planned weeks in advance, with seating charts, menus and toasts subject to careful scrutiny. So imagine Britain’s surprise when Mikhail Gorbachev made an unannounced, spontaneous visit to the prime minister’s residence at 10 Downing Street in London on Dec 20, 1984. This happened in December 1984, when the future Soviet leader - chief architect of the liberalization program known as perestroika - made a landmark trip to Britain. Gorbachev’s impromptu appearance at the prime minister’s home was revealed in a confidential telegram made public Friday Jan 2, 2014 by the National Archives under the “30-year rule” for declassifying secret documents. It was sent on an urgent basis to Thatcher’s party in Hong Kong, where she was traveling. She had met Gorbachev 4 days earlier in England. (AP Photo/File)