British nationalities include the status of British national (overseas) or BN(O). Despite being British nationals (and Commonwealth citizens), individuals with this nationality may not in fact be British citizens.
BN(O) status was set up for British overseas territories citizens who were connected by Hong Kong to the United Kingdom.
The changes allowed these individuals to register before the 1st of July 1997 as a British national (overseas).
There were some British overseas territories citizens from Hong Kong that did not register as British nationals (overseas).
As such, they had no other nationality or citizenship on the 30th of June 1997. So, these individuals became British overseas citizens on the 1st of July 1997.
Note: British nationality law does not allow you to apply to become a British national (overseas). Even so, some exceptions apply for those who already hold that status.
British nationals (overseas) can:
But, holding this particular status means:
As a British national (overseas), you may be able to register as a British citizen if you meet certain conditions. You can check your eligibility to become a British citizen in a different section.
British National (Overseas) Status Explained and Simplified for Easy Understanding