Leonard Lloyd Duvall OBE (born 26 September 1961)[2] is a British Labour and Co-operative politician who has been deputy chair of the London Assembly since May 2024.

Duvall is a former chair of both the Metropolitan Police Authority[3] and the London Labour Party Regional Board.

He is leader of the Labour Group on the London Assembly, chair of both the EU Exit Working Group[12] and the GLA Oversight Committee, and Deputy Chair of the Budget and Performance Committee and the Budget and Monitoring Sub-Committee.

[13] Outside the London Assembly, he is a non-executive director of Tilfen Land, a property development company and a board member of the Royal Artillery Museums Trust,[14] his father and grandfather having served as gunners in the Royal Artillery.

[5] In 2021 Duvall was praised by the Panel investigating the unsolved 1987 murder of Daniel Morgan for giving effective direction while chair of the Metropolitan Police authority.