In 2006, she was elected as a Conservative councillor for Westminster City Council, representing Warwick ward, a safe seat covering an area in Pimlico.[8] She remained a councillor until she stood down at the 2022 election.[9][10][11] Aiken held various positions on the Council, including being the Cabinet Member for Children's Services and Public Protection & Licensing, as well as being the leader of the Council from January 2017 to January 2020.[12][13]
Aiken was elected at that election with 39.9% of the vote and a majority of 3,953.[19]
In Parliament, she was a member of the Women and Equalities Committee until September 2020. She was appointed vice chairman of the Conservative Party in October 2020, with responsibility for women. Aiken also sits on the UK Delegation for the Council of Europe and is a Member of the House of Commons Commission.
Aiken has pushed for legislation on child safety.[20] She has urged the Tories to increase assistance for private renters.[21] In June 2021, she joined the Monken Hadley Common Bill Unopposed Bill Committee.[22]
Aiken has lived in Pimlico for over twenty years, and prior to that, lived in the Barbican.[7][14] She lists her recreations as "walking".[2]
She married Alexander Stuart Aiken in 2000. Since 2013, he has been executive director of government communications at the Cabinet Office for the UK Government. He resigned from the role of a Government Communicator in February 2024 to work as a communications adviser for the UАЕ.[25] From 2000 to 2012, he was director of communications and strategy for Westminster City Council, whilst his wife was a councillor there. Before that, he worked for the Conservative Party as head of its campaigns unit and its press office.[26] The couple have a daughter and a son.[2]