“..for the reasons given by Lord Phillips, it seems to me that, where there are no issues of primary fact, application of this test will normally admit of only one answer, and a challenge to the Secretary of State’s decision will normally stand or fall on establishing irrationality. Accordingly, I agree that if, in a case where the primary facts are not in dispute, the court concludes that….a claim has ‘some reasonable prospect of success’, it is hard to think of any circumstances where it would not quash the Secretary of State’s decision to the contrary. However, I would again be reluctant to suggest that there is a hard and fast rule to that effect.”