"There is a general presumption against ousting the jurisdiction of the courts so that statutory provisions which purport to exclude judicial review are construed restrictively. There are, however, certain areas of governmental activity, national security being the paradigm, which the courts regard themselves as incompetent to investigate, beyond an initial decision as to whether the Government's claim is bona fide. In this kind of non- justiciable area judicial review is not entirely excluded, but very limited. It has also been said that powers conferred by the Royal Prerogative are inherently unreviewable but since the speeches of the House of Lords in Council of Civil Service Unions v. Minister for the Civil Service this is doubtful. LORDS Diplock, Scarman and ROSKILL appeared to agree that there is no general distinction between powers, based upon whether their source is statutory or prerogative but that judicial review can be limited by the subject-matter of a particular power, in that case national security. Many prerogative powers are in fact concerned with sensitive, non-justiciable areas, for example, foreign affairs, but some