The House of Commons rejected the amendments on 18 November and the bill was granted Royal Assent later that day through the use of the Parliament Acts.

[7] Nine judges were selected to hear the appeal, as opposed to the usual number of five, due to the significant constitutional issues the case raised.

[16] Professor Mullen therefore suggests that it is at first glance surprising that standing was not contested: the appellants brought proceedings in their personal capacities, yet had not even been threatened with prosecution.

Moreover, the recent expansion of standing for issues of public interest, such as the validity of an Act of Parliament, would have made a successful challenge more difficult.

[3]: 4 Another preliminary issue, that of whether the House of Lords had jurisdiction to challenge the validity of an Act of Parliament, was also not argued by the Attorney General in a move described by Ekins as "an extraordinary concession".

[11]: 112  The enrolled bill rule, affirmed in Pickin v British Railways Board,[17] had established that the courts could not examine the procedure by which legislation had been passed.

[1]: 2  Lord Bingham found that the phrase "become an Act of Parliament on the Royal Assent being signified" denoted primary legislation.

[18]: 564 The House of Lords rejected the Court of Appeal's finding that there was a distinction between non-fundamental constitutional changes, which could be passed using the Parliament Act 1911, and fundamental constitutional changes, which could not; Lord Bingham argued that "the ... solution finds no support in the language of the Act, in principle or in the historical record".

[7]: [31]  Of the nine judges, only Lord Carswell suggested that there may be implied limits to the use of the Parliament Acts, but acknowledged the difficulty of defining the extent of these restrictions.

[7]: [61] [19]: 721  Lord Bingham was the only judge to explicitly reject the validity of this implied limitation, arguing that there were no reasons for preventing the alteration of the clause limiting the subject matter of full Acts of Parliament and that "it cannot have been contemplated that if, however improbably, the Houses found themselves in irreconcilable deadlock on this point, the government should have to resort to the creation of peers".

[1]: 2 Cosmo Graham argues that Jackson could be seen as "a constitutional curio, dealing with an obscure point, which is now effectively settled in favour of the Executive"; the case, from this perspective, is of no practical consequences given the limited use of the Parliament Acts and plans to further reduce the power of the House of Lords to delay bills.

However, he suggests that Jackson is part of a trend of increased willingness by the judiciary to examine the claimed existence of executive powers and "to push at the borders of traditional techniques of judicial interpretation".

Four recent cases had found that "in the absence of express language or necessary implication to the contrary, the courts [will] presume that even the most general words were intended to be subject to the basic rights of the individual".

In exceptional circumstances involving an attempt to abolish judicial review or the ordinary role of the courts, the Appellate Committee of the House of Lords or a new Supreme Court may have to consider whether this is a constitutional fundamental which even a sovereign Parliament acting at the behest of a complaisant House of Commons cannot abolish.

The fact that your Lordships have been willing to hear this appeal and to give judgment upon it is another indication that the courts have a part to play in defining the limits of Parliament's legislative sovereignty.

[7]: [104], [107] Lord Hope also argued that Parliament should not be able to pass legislation that "is so absurd or so unacceptable that the populace at large refuses to recognise it as law".

The courts will treat with particular suspicion (and might even reject) any attempt to subvert the rule of law by removing governmental action affecting the rights of the individual from all judicial scrutiny.

[3]: 14–15  Lord Bingham affirmed that "the bedrock of the British constitution is ... the supremacy of the Crown in Parliament"[7]: [6]  while Lord Carswell stated: I do not, and I have no doubt your Lordships do not, have any wish to expand the role of the judiciary at the expense of any other organ of the State or to seek to frustrate the properly expressed wish of Parliament as contained in legislation.

The attribution in certain quarters of such a wish to the judiciary is misconceived and appears to be the product of lack of understanding of the judicial function and the sources of law which the courts are bound to apply.

[9]: 194–195 Christopher Forsyth suggests that the limitations of the 1911 Act could be explained by the common law constitutionalism theory, but argues that "if the judiciary frustrated by the failings of the elected legislature were to assert a power to hold Acts of Parliament invalid it would be stepping from law into politics and the outcome of its efforts impossible to predict".

The argument from legitimacy highlights that Parliament's supremacy depends on the democratic and accountable nature of legislature; anything that undermines this status would invalidate the applicability of the doctrine.

[8]: 572  The argument based on the current hypothesis of constitutionalism reasons that no authority should be allowed to violate fundamental rights in a democratic society: they are essential features that cannot be removed, even by a supposedly sovereign Parliament.

This view was also expressly endorsed in Jackson by Lord Hope, who regarded Parliament's sovereignty as subject to the rule of law.