The Cabinet Secretary is the top most executive official and senior-most civil servant in the Government of India. The Cabinet Secretary is the ex-officio head of the Civil Services Board, the Cabinet Secretariat, the Indian Administrative Service (IAS) and head of all civil services under the rules of business of the Government of India. The Cabinet Secretary is under the direct charge of the Prime Minister. Though there is no fixed tenure, the average tenure of the Cabinet Secretary has been less than 3 years. His or her tenure however, can be extended.