In this case the Court set out guidance as to the scope of a courts power to interfere with a decision on the ground of insufficiency of inquiry. Neill J said at para 409
"(1) The duy to make inquiries is to make such inquiries as are necessary to satisfy the authority ... It follows therefore that as it is the authority which have to be satisfied the scope and scale of the inquiries is, primarily at least, a matter for them. But the introduction of the word 'necessary' indicates that there is a standard which those inquiries must observe. In other words, the inquiries must be those which are 'necessary' to enable the authority to make a decision.
(2) If the court is to intervene by way of judicial review, it must be on the basis, as I see it, that the inquiries have not reached the required standard in the circumstances of the case ...
(3) In deciding how a reasonable authority would have acted and what inquiries they would have made in the circumstances, the court must have regard to the speech of Lord Brightman in AC 484 where he said at p.518:
'... it is not, in my opinion, appropriate that the remedy of judicial review, which is a discretionary remedy, should be made use of to monitor the actions of local authorities under the Act save in the exceptional case ... Where the existence or non-existence of a fact is left to the judgment and discretion of a public body and that fact involves a broad spectrum ranging from the obvious to the debatable to the just conceivable, it is the duty of the court to leave the decision of that fact to the public body to whom Parliament has entrusted the decision-making power save in a case where it is obvious that the public body, consciously or unconsciously, are acting perversely' ...".