Hong Kong Basic Law Article 23 (Chinese: 香港基本法第二十三條) is an article in the Basic Law of Hong Kong. It states that the Hong Kong Special Administrative Region "shall enact laws on its own to prohibit any act of treason, secession, sedition, subversion against the Central People's Government, or theft of state secrets, to prohibit foreign political organizations or bodies from conducting political activities in the Region, and to prohibit political organizations or bodies of the Region from establishing ties with foreign political organizations or bodies." An attempt to implement the article was the National Security (Legislative Provisions) Bill 2003 which caused a great controversy and a massive demonstration on 1 July 2003. Since then, the bill of implementing the article has not been reintroduced.
The Article 23 of the Basic Law (BL 23) states:
The Hong Kong Special Administrative Region shall enact laws on its own to prohibit any act of treason, secession, sedition, subversion against the Central People's Government, or theft of state secrets, to prohibit foreign political organisations or bodies from conducting political activities in the Region, and to prohibit political organisations or bodies of the Region from establishing ties with foreign political organisations or bodies.
Before 1997, the British colonial government introduced the Crimes (Amendment)(No.2) Bill 1996 in an attempt to concretize the concepts of "subversion" and secession" by confining them to actual violent conduct but of no avail. It failed as it was strongly opposed by Beijing and thus left a vacuum in the present legislation.
In February 2003, the HKSAR government proposed the National Security (Legislative Provisions) Bill 2003 to the Legislative Council which aimed to amend the Crimes Ordinance, the Official Secrets Ordinance and the Societies Ordinance pursuant to the obligation imposed by Article 23 of the Basic Law of the Hong Kong Special Administrative Region of the People's Republic of China and to provide for related, incidental and consequential amendments. The proposed bill caused considerable controversy in Hong Kong and a massive demonstration on 1 July 2003. In the aftermath, Liberal Party chairman James Tien resigned from the Executive Council and the bill was withdrawn after it became clear that it would not get the necessary support from the Legislative Council for it to be passed. The bill was then shelved indefinitely.
There are calls for reintroducing the national security bill after the 2003 setbacks from the pro-Beijing camp occasionally. After the Beijing interpretation of the Basic Law in November 2016 over the Legislative Council oath-taking controversy to eject two pro-independence legislators from the legislature on the basis that "[Beijing] will absolutely neither permit anyone advocating secession in Hong Kong nor allow any pro-independence activists to enter a government institution," Chief executive Leung Chun-ying said Hong Kong would enact Article 23 targeting pro-independence movement in Hong Kong.
In April 2018, Hong Kong member of the National People's Congress Standing Committee (NPCSC) Tam Yiu-chung also urged Hong Kong to urgently implement Article 23 of the Basic Law to criminalise a series of acts including sedition, treason and subversion following the remarks of Occupy Central with Love and Peace co-founder Benny Tai on Hong Kong independence when he said China's various ethnic groups could exercise their right to self-determination after the end of the "dictatorship" in China. "We could consider going independent, being part of a federal system or a confederation system similar to that of the European Union," he said.