If the court takes upon itself the task of deciding the nature of the document, then it will be taking upon itself the very grave duty of deciding a vital question as to what are the affairs of State without having the necessary material before it or without knowing the exigen cies of the public service or the effect of the disclosure of the State secret or how far the disclosure will injure the public interests and it may thus unwittingly become the instrument of giving publicity to something which the head of the department considered injurious to the public interests, the law having given to the head of the department concerned to make this determination ' No doubt the discretion is wide and covers all classes of documents which may fall within the phrase "affairs of State", some noxious and others innocuous and may even appear to be unduly restrictive of the rights of the litigant but if that is the law the sense of responsibility of the official concerned and his sense of fair play has to be trusted.