Those who have moved across the world to the United Kingdom on a British National (Overseas) visa will find efforts have been made to make them feel welcome as it specifically recognizes Hongkongers as Commonwealth citizens who are eligible to vote.
According to a note on the democratic rights of Hongkongers published by the Greater London Authority, Hongkongers living in the UK on a BNO visa can vote in all UK elections.
This is because they are considered Commonwealth citizens, meaning they can stand for office and cast their vote in local council elections, mayoral and assembly elections as well as UK general/ parliamentary elections. During the registration process, they'll be asked their date of birth, national insurance number, current and previous addresses as well as other personal particulars.
If these aren't available, for example because the aspiring voter has only just moved to the country, they will have to provide another identification document and two "financial/social history documents" such as bank statements.
However, BNO holders who wish to find their groove in UK life as soon as possible have to be careful as there is a deadline for voter registration and that is usually 12 working days before an election.