They are the principal authorities in Greater London and have responsibilities including education, housing, planning, highways, social services, libraries, recreation, waste, environmental health and revenue collection.

Michael Pavey, a Labour councillor for Barnhill ward, resigned in November 2019, citing family reasons.

[3] Another Labour councillor for the same ward, Sarah Marquis, resigned days later, citing family and personal reasons.

[4] A Labour councillor for Wembley Central ward, Luke Patterson, resigned in the same month citing personal reasons.

[5][6] By-elections to replace all three, in addition to James Allie, a Labour councillor for Alperton who resigned, were held on 23 January 2020.

[7] The Labour candidate to replace Allie, Chetan Harpale, was suspended from his party during the campaign to investigate alleged Islamophobia.

[8][9] In 2021, a Labour councillor for Brondesbury Park, Kieron Gill, resigned, declining to explain his reasons.

All registered electors (British, Irish, Commonwealth and European Union citizens) living in London aged 18 or over were entitled to vote in the election.