But before Hong Kong was returned, Britain and China agreed to set up “one country, two systems.” “Two Systems” refers to an agreement that Hong Kong would enjoy a “high degree of autonomy,” with its social and economic systems and way of life remaining unchanged for 50 years, from 1997 to 2047. During the 2014 Umbrella Revolution, a campaign against mainland China`s perceived violations against the HKSAR, Chinese officials concluded for the first time that China considered the joint statement to be “untested,” according to a British lawmaker.  This conclusion was deemed “clearly erroneous” by a senior Hong Kong lawyer and rejected by the British Foreign Secretary, who said the document was a legally binding agreement to be respected.   Rita Fan, then Hong Kong`s sole representative on the Standing Committee of the National People`s Congress in Beijing, argued that Britain`s prudential responsibility had been abandoned and that the joint declaration also did not provide for universal suffrage.  On December 19, 1984, after years of negotiations, the British and Chinese leaders signed a formal pact authorizing the colony`s turnover in 1997 in exchange for the formulation of a “One Country, Two Systems” policy by the Chinese Communist government. Prime Minister Margaret Thatcher called the agreement “a milestone in the life of the territory, in Anglo-Chinese relations and in the history of international diplomacy.” Hu Yaobang, the general secretary of the Communist Party of China, called the signing a “day of red letters, an opportunity of great joy” for the billion Chinese. One of the major achievements has been to ensure the continuity of independent justice in Hong Kong, including agreements in the areas of commercial shipping, civil aviation, nuclear materials, whaling, underwater telegraph, space and many others. It also approved a network of bilateral agreements between Hong Kong and other countries. Within the framework of these agreements, some 200 international conventions were concluded after 30 June 1997 on the further application of some 200 international conventions to the HKSAR. .