Opinion | For Hong Kong today, the Sino-British Joint Declaration is just a piece of paper
- Despite having different points of view, China and the UK papered over their differences with constructive ambiguity to sign the Joint Declaration
- Beijing’s mistake was perhaps trusting that Hong Kong could tackle social injustice on its own, against a backdrop of great power competition

Treaty for a Lost City, a new book by Chinese University of Hong Kong law professor C.L. Lim, is a meticulously researched volume on how the Sino-British Joint Declaration came into being and whether it still has the force of law on both sides.
There is a presumption that the Joint Declaration granted Hong Kong democratic rights. The legal story is much more complex. This book draws on materials, including files from the British National Archives, the Basic Law and the International Covenant on Civil and Political Rights, and lays out the facts and positions for the reader to judge who is right or wrong.
Cities and states are defined by legal constitutions, communal values, geography, culture and history. Prior to 1841, Hong Kong was indisputably part of China. Although Hong Kong Island was ceded under the Treaty of Nanjing after the first Opium War, the expiry of the 99-year lease on the New Territories meant that Britain could not hold onto Hong Kong after 1997.
The current government of China, like the previous one, did not recognise any unequal treaty with the Western powers, but adopted the face-saving position that “a sovereign may delegate under international law such control or authority to another for a limited period”. Once this sovereignty was resumed, however, the People’s Republic of China would not brook any interference in sovereign matters.
