The West Mercia Police and Crime Commissioner announced on 30 June that she was his preferred candidate as the next Chief Constable of West Mercia Police.[3] Mills' appointment was confirmed on 13 July, making her the first woman to lead West Mercia.[5][6] On 8 August 2023 she announced she would be leaving West Mercia Police to return to the Metropolitan Police as an Assistant Commissioner.[7][2]