The Indian Administrative Service (abbreviated as IAS) is the premier administrative civil service of the Government of India. IAS officers hold key and strategic positions in the Union Government, States and public-sector undertakings. Like in various countries (example UK) following Parliamentary system, IAS as the permanent bureaucracy in India forms an inseparable part of the executive branch of the Government of India thus providing continuity and neutrality to the administration. Unlike Candidates selected to other civil services, a person once appointed to Indian Administrative Service or Indian Foreign Service (IFS) becomes ineligible to reappear in Civil Services Examination conducted by Union Public Service Commission because there are no higher civil services other than aforementioned two services under Government of India.