The Agreement entered into force on 27 May 1985 and was registered with the United Nations by the Governments of China and the United Kingdom on 12 June 1985. One of the most important achievements has been to ensure the continuity of the independent judiciary in Hong Kong, including agreements in the legal fields of merchant shipping, civil aviation, nuclear materials, whaling, underwater telegraph, space and many others. He also agreed on a network of bilateral agreements between Hong Kong and other countries. Under these agreements, arrangements have been made for the further application of some 200 international conventions to the Hong Kong Special Administrative Region after 30 June 1997. Hong Kong is expected to continue to participate in various international organizations even after the handover. After the Asian financial crisis of 1997, the measures taken in Hong Kong were taken in full cooperation with the Government of Central China. This did not mean that the Chinese government dictated what to do and therefore always followed the points of the declaration.  The list included representatives of the Hong Kong government, members of the Legislative and Executive Council, presidents of Hong Kong and Shanghai Banking Corporation and Standard Chartered Bank, prominent businessmen such as Li Ka-shing, Pao Yue-kong and Fok Ying-tung, and Martin Lee Chu-ming and Szeto Wah. But before Hong Kong was returned, Britain and China agreed to introduce „one country, two systems.“ The agreement, signed in 1984, was to apply until 2047. But it seems that these promises are fading. In recent years, critics say, Beijing has taken brazen steps to invade Hong Kong`s political system and crack down on dissent.
These measures sparked massive protests in Hong Kong and were condemned internationally. In 2020, Beijing passed a controversial national security law and arrested dozens of pro-democracy activists and lawmakers, dampening hopes that Hong Kong would one day become a full-fledged democracy. The Chinese embassy in Britain quickly refuted what it called „baseless slander.“ Britain quickly returned to this unofficial part of the agreement, attacking the walled city of Kowloon in 1899, only to find it abandoned. They did nothing with it or the outpost and therefore raised the issue of ownership of the walled city of Kowloon directly in the air. The outpost consisted of a yam and buildings that developed into low- and densely populated neighborhoods from the 1890s to the 1940s. Some political analysts thought it was urgent to reach an agreement because there were fears that without a deal, Hong Kong`s economy would collapse in the 1980s. Concerns about land ownership in the New Leased Territories have also contributed to the problem. Although discussions about Hong Kong`s future began in the late 1970s, the final timing of the Joint Declaration was influenced by real estate and economic factors rather than geopolitical necessities.
 During talks with Thatcher, China planned to invade Hong Kong and conquer it if the negotiations sparked unrest in the colony. Thatcher later said that Deng bluntly told her that China could easily take Hong Kong by force, explaining that „I could go there this afternoon and take the whole lot,“ to which she replied that „there is nothing I can do to stop you, but the eyes of the world will now know what China looks like.“  The Sino-British Joint Declaration itself does not have a mechanism approved by both sides to ensure its compliance. Although the agreement is registered with the United Nations, it did not contain any United Nations oversight mechanism. Therefore, only the signatories of the declaration have the right to assert possible violations of the conditions. This group was a connecting, not a power, body where each party could send up to 20 support staff. It should meet at least once a year in each of the three sites (Beijing, London and Hong Kong). Since July 1, 1988, it has been based in Hong Kong. It should also support the Hong Kong Special Administrative Region in maintaining and developing economic and cultural relations and conclude agreements in this regard with relevant States, regions and international organizations, and could therefore establish specialized sub-groups. Between 1985 and 2000, the Joint Liaison Group held 47 plenary meetings, including 18 in Hong Kong, 15 in London and 14 in Beijing. During the 2014 Umbrella Revolution, a campaign against mainland China`s perceived violations in the Hong Kong Special Administrative Region, Chinese officials concluded for the first time that China considered the Joint Declaration „void,“ according to a British lawmaker.  This finding was dismissed as „clearly false“ by a senior Hong Kong jurist and rejected by the British Foreign Secretary, who said the document was a legally binding agreement that had to be respected.
  Rita Fan, then Hong Kong`s sole representative on the Standing Committee of the National People`s Congress in Beijing, claimed that Britain`s oversight responsibility had expired and that the Joint Declaration did not provide for universal suffrage.  The British government`s response to the recent protests in Hong Kong drew attention to the 1984 Sino-British Joint Declaration. This backgrounder examines what the declaration is and the concerns about its status. .