The Court will give decision-makers a degree of leeway and will not consider whether a decision is absolutely correct or one that the Court itself would have necessarily made. It will bear in mind that where a democratically-elected legislature has given discretion to a particular decision-maker (i.e. a public authority), the discretion remains the decision-maker’s. It is not for the Court to exercise the discretion instead. The Court will not retake the public authority’s decision on the facts, but in appropriate cases (e.g. those involving a person’s rights or the rule of law) it will look very closely at the way the facts have been established and the logic of the conclusions drawn from them.
In giving decision-makers this leeway – the extent of which will vary from case to case – the Court have recognised that when different reasonable people are given the same set of facts, it is perfectly possible for them to come to different conclusions without being unreasonable. This means that not every mistaken exercise of judgment is unreasonable. As such, a range of lawful decisions may be within the discretion of the decision-maker (i.e. “within the range of reasonable responses”), but the width of that range will depend on the context of the decision.
Where the Court finds that the decision was unreasonable it may choose to quash the decision, leaving none in its place. The decision-maker may (or often, must) then reconsider the decision, taking into account any guidance given by the Court and applying more reasonable principles. It may be expected that the decision-maker will not remake the original unreasonable decision.