text: 172. The Government reserves the right to continue to apply such immigration legislation governing entry into, stay in and departure from the United Kingdom as it may deem necessary from time to time and, accordingly, its acceptance of article 12, paragraph 4, and of the other provisions of the Covenant is subject to the provisions of any such legislation as regards persons not at the time having the right under the law of the United Kingdom to enter and remain in the country. The United Kingdom also reserves a similar right in regard to each of its dependent territories. 173. The position at the time of the second periodic report was as follows. The British Nationality Act 1981 had replaced the status of citizen of the United Kingdom and Colonies (CUKC), created by the British Nationality Act 1948, by three separate citizenships: (a) British citizenship: for those closely connected with the United Kingdom; acquired mainly by birth in the United Kingdom of a parent who is a British citizen or settled there; (b) British Dependent Territories citizenship (BDTC): for persons connected with the dependencies; (c) British Overseas citizenship (BQC): for those CUKCs not having the above connections with the United Kingdom or dependencies; the 1981 Act had also preserved the status of: (d) British subject: mainly persons born before 1949 who did not subsequently become a CUKC or a citizen of a Commonwealth country; and (e) British Protected Person (BPP): persons connected with former protectorates or former trust territories; subsequently, however, a new category of citizenship was created on 1 July 1987 by the Hong Kong (British Nationality) Order 1986: (f) British Nationals (Overseas) (BNO): persons who are BDTCs solely by connection with Hong Kong, who may then apply to register as BNOs before 1 July 1997. 
analysis: This text appears to be discussing the citizenship and immigration laws of the United Kingdom, specifically the changes made by the British Nationality Act 1981 and the creation of a new category of citizenship, British Nationals (Overseas). It also mentions the rights reserved by the Government to continue applying immigration legislation and the connection to dependent territories. Given the focus on citizenship, immigration, and nationality, it is likely that the text is related to a category that deals with these topics.