[I]t is not clear from those paragraphs whether Morris J was saying, or suggesting, that there was some material inconsistency between the joint advice and the other advices received by the Attorney-General, or between the factual bases upon which the various advices were given. Yet he appeared to raise, as a matter for serious consideration, the possibility that there was some "difference" between the joint advice and other advices.
...
There are obvious difficulties in giving the phrase "public interest" as it appears in s 50(4) a fixed and precise content. It is sufficient to say here that the assumption by the Attorney-General of political accountability by the putting out of the press release may, in the circumstances, enliven s 50(4). If there were nothing more to it than that Morris J was saying that the very existence of a number of advices meant that, in order to "clear the air" and dispel any speculation about possible inconsistency, they should all be released then the Court of Appeal should have rejected that reasoning. If, however, there were some material difference in the advices, or the facts on which they were based, then, depending on the nature and extent of that difference, it is not impossible that an aspect of the public interest could require its revelation ... It could not be said that, as a matter of principle, no inconsistency between the various advices could possibly have required the disclosure of all or any of them. The Attorney-General, in his press release, referred, for an obvious and legitimate purpose, to certain legal advice as recommending the course that was finally taken. If it had been the case that the Government had received other and materially different legal advice then, depending on the nature and extent of the difference, it is possible that this could have been a relevant consideration in deciding the requirements of the public interest under s 50(4). This is not to say that the existence of differences would necessarily require disclosure. Rather, the existence of such differences as might require disclosure, having been raised obliquely by Morris J, could not be disregarded as legally impossible ...
The Court of Appeal was not obliged to remit the matter to the Tribunal. It was empowered to deal with the s 50(4) issue itself. In doing so, because of what Morris J had said about the possibility of inconsistency, the Court of Appeal should have examined the documents for itself. Having done so, it may well have concluded that the public interest did not require access to the documents and that either there were no material differences or that such differences did not require disclosure of the documents ...[8]