The next point is, what are the well established rules which help the court to decide whether a particular document pertains to affairs of State or not? The following relevant rules may be extracted from 455 the decision of the Judicial Committee in Robinson 's case (1): (1) the privilege is a narrow one most sparingly to be exercised; (2) the principle of the rule is concern for public interest and the rule will accordingly be applied no further than the attainment of that object requires; (3) as the protection is claimed on the broad principle of State policy and public convenience, the papers protected, as might have been expected, have usually been public official documents of a political or administrative character; (4) its foundation is that the information cannot be disclosed without injury to the public interests and not that the documents are confidential or official, which alone is no reason for their non production; (5) even in the case of documents relating to the trading, commercial or contractual activities of a State, it is conceivable that there may be some plain overruling principle of public interest.