"76. … the appropriate and principled approach is for the court to allow both the Government and Parliament a reasonable amount of time in which they have the opportunity to enact national legislation to correct the defects which exist and which are incompatible with EU law. …. 85. … there are strong constitutional reasons, and not only practical ones, for declining to grant any order or declaration which would have the effect of immediately disapplying the provisions of Part 4 of the 2016 Act."
"The primacy and uniform application of EU law would be undermined if national courts had the power to give provisions of national law primacy in relation to EU law contravened by those provisions, even temporarily."
"132 … the interpretation which, in the exercise of the jurisdiction conferred on it by Article 267 TFEU, the Court gives to rules of EU law clarifies and defines the meaning and scope of those rules as they must be or ought to have been understood and applied from the time of their entry into force. It is only exceptionally that the Court may, in application of the general principle of legal certainty inherent in the EU legal order, be moved to restrict for any person concerned the opportunity of relying on a provision which it has interpreted with a view to calling into question legal relationships established in good faith. Two essential criteria must be fulfilled before such a limitation can be imposed, namely that those concerned should have acted in good faith and that there should be a risk of serious difficulties. … 135. By virtue of the principle of primacy of EU law, rules of national law, even of a constitutional order, cannot be allowed to undermine the unity and effectiveness of EU law … Even assuming that overriding considerations of legal certainty are capable of leading, by way of exception, to a provisional suspension of the ousting effect which a directly applicable rule of EU law has on national law that is contrary thereto, the conditions of such a suspension can be determined solely by the Court …"
"Their Lordships regard the use of precedent as an indispensable foundation upon which to decide what is the law and its application to individual cases. It provides at least some degree of certainty upon which individuals can rely in the conduct of their affairs, as well as a basis for orderly development of legal rules. Their Lordships nevertheless recognise that too rigid adherence to precedent may lead to injustice in a particular case and also unduly restrict the proper development of the law. They propose, therefore, to modify their present practice and, while treating former decisions of this House as normally binding, to depart from a previous decision when it appears right to do so. In this connection they will bear in mind the danger of disturbing retrospectively the basis on which contracts, settlements of property and fiscal arrangements have been entered into and also the especial need for certainty as to the criminal law. This announcement is not intended to affect the use of precedent elsewhere than in this House."
"it would not be just or appropriate for the Court simply to give the Executive a carte blanche to take as long as it likes in order to secure compliance with EU law. The continuing incompatibility … needs to be remedied within a reasonable time."