Duncan was first elected to Hillingdon Council in 2014 and re-elected in 2018 to represent Northwood Hills ward where he lives.
Duncan is the Conservative Group Chief Whip at Hillingdon Council. Prior to this appointment, Duncan served as Vice Chairman of the Council's Social Care, Housing & Public Health Policy Overview Committee and the North Planning Committee.
Duncan has previously served as a Governor of Hillside Junior School and is a member of the Ruislip Woods Management Advisory Group.
Duncan's political priorities include supporting small businesses and protecting local green spaces.
Duncan is married and has two young daughters.