"Where, as here, there is no dispute of primary fact, the question of whether or not a claim is clearly unfounded is only susceptible to one rational answer. If any reasonable doubt exists as to whether the claim may succeed then it is not clearly unfounded. It follows that a challenge to the Secretary of State's conclusion that a claim is clearly unfounded is a rationality challenge. There is no way that a court can consider whether her conclusion was rational other than by asking itself the same question that she has considered. If the court concludes that a claim has a realistic prospect of success when the Secretary of State has reached a contrary view, the court will necessarily conclude that the Secretary of State's view was irrational."
“19. … But for the present, at least, the last word on the subject has now been said in EB (Kosovo). While it is of course possible that the facts of any one case may disclose an insurmountable obstacle to removal, the inquiry into proportionality is not a search for such an obstacle and does not end with its elimination. It is a balanced judgment of what can reasonably be expected in the light of all the material facts. … 24. EB (Kosovo) now confirms that the material question in gauging the proportionality of a removal or deportation which will or may break up a family unless the family itself decamps is not whether there is an insuperable obstacle to this happening but whether it is reasonable to expect the family to leave with the appellant …” 25 At the end of his judgment in AF (Jamaica) v Secretary of State for the Home Department[2009] EWCA Civ 240 , itself a deportation case, Rix LJ, having referred to EB (Kosovo) and to VW (Uganda) and AB (Somalia), continued: “42. … Albeit those cases all arose in the context of removals rather than deportations and did not raise the issue of proportionality against the background of the commission of a serious criminal offence, they each in their own way dethrone the significance of the test of ‘insurmountable obstacles’ or emphasise the importance of the test of whether it is reasonable to expect a spouse or child to depart with the family member being removed. The ultimate test remains that of proportionality …”