From screaming headlines to more sober assessments, much has been written about this decision of the High Court since it was delivered earlier this month. Early in December, an appeal by the government is to be heard by the Supreme Court.
The judgment is 31 pages long and comprises 111 paragraphs. The aim of this summary is to provide a more easily absorbed exposition of the main elements of the court's decision.
1. The sole issue to be decided was the legal one of whether the UK government, under UK constitutional law, is entitled – without reference to Parliament – to use the Crown's royal prerogative power to give notice, under article 50 of the Treaty on European Union, of the UK's intention to withdraw from the EU. The court decided that the government does not have such an entitlement.
2. Both sides agreed that (and the court therefore made its decision on the basis that):
(i) under the UK's constitution, that legal issue was properly one for the courts to decide;
(ii) notification under Article 50 cannot be withdrawn, once given;
(iii) such notification cannot be conditional, e.g. upon later Parliamentary approval.
3. The government's legal team emphasised that if, following Article 50 notification, an agreement were reached between the UK and the EU under Article 50.2 as to the "arrangements for ... withdrawal, taking account of the framework for [their] future relationship", it would very likely be a treaty requiring ratification and, as such, subject to veto by Parliament under the Constitutional Reform and Governance Act 2010. So, Parliament would have its say. However, that did not assist the government's case because if no such agreement were reached, or if there were an agreement and Parliament vetoed it, the notification to leave would remain effective and, by virtue of Article 50.3, the UK would exit the EU two years after notice had been given.
4. The court noted that:
(i) the most fundamental rule of UK constitutional law is that Parliament is sovereign and that legislation enacted by Parliament is supreme. In the European Communities Act 1972, Parliament had provided for precedence of EU law over its own legislation, but had retained the power to revoke that provision and therefore remained sovereign and supreme;
(ii) quoting from an earlier case, the royal prerogative "is really a relic of a past age, not lost by disuse, but only available for a case not covered by statute". As was confirmed in the 1688 Bill of Rights, the King or Queen's government cannot dispense with or change statute or the common law without the consent of Parliament;
(iii) the conduct of international relations and the making and unmaking of treaties on behalf of the UK are, generally, matters for the government under the exercise of the Crown's prerogative power, but only to the extent that the result is neither to change domestic law nor to grant or deprive individuals of legal rights – as only Parliament can do that; and
(iv) hence, it had been necessary for Parliament to enact the 1972 Act in order to give effect within the UK to the treaty which the government entered into when joining the European Communities (the predecessor to the EU). That included the imposition of obligations and the granting of rights to UK citizens, the 1972 Act creating the concept of an "enforceable EU right".
5. It was common ground between the parties that, if the UK withdraws from the EU pursuant to notification under Article 50, there will no longer be any enforceable EU rights. The government argued that some rights are, in theory, capable of replication under domestic UK law, but the court's view was that this was not guaranteed and that exact replication was not possible. The government accepted that some rights could not be replicated and would be lost.
6. The government argued that:
(i) under the 1972 Act, the content of EU rights is defined by reference to the EU treaties;
(ii) Parliament must have intended, therefore, that continued enjoyment of such EU rights within the UK was conditional upon the UK's continued membership of the EU;
(iii) by not, in 1972, removing the government's prerogative power to withdraw the UK from the EU treaties, Parliament had intended that EU rights within the UK would be vulnerable to removal by the government exercising that power.
7. The court rejected the government's argument for several reasons:
(i) Legislation must be interpreted in accordance with constitutional principles, the presumption being that Parliament intended to uphold, rather than undermine, them. The stronger the principle, the stronger the presumption;
(ii) That presumption is particularly strong in the case of a constitutional statute, such as the 1972 Act, which is only capable of repeal by express language or necessary implication in a later statute;
(iii) The government's argument overlooked the constitutional principle that it (the government) cannot use the royal prerogative power to alter domestic UK law. Parliament cannot have intended that the continued existence within the UK of the EU rights it introduced into the UK under the 1972 Act would be subject to the choice of the government (without further reference to Parliament) as to whether or not to take the UK out of the EU treaties;
(iv) The government's argument that it can, through the exercise of the royal prerogative, bring about major changes in domestic UK law, also overlooked the constitutional principle that the exercise of prerogative power in the conduct of international relations can have no effect in domestic law;
(v) Interpreting the 1972 Act in the light of that constitutional background, it was clear that Parliament had intended to legislate so as to introduce EU law into domestic law in such a way that it could not be undone by the exercise of royal prerogative power;
(vi) The government's argument did not rely on any express wording in the 1972 Act because there was none to support it. Instead, it relied on the absence of wording and on implications which the court decided could not be made, given the constitutional background;
(vii) The court pointed to text in the 1972 Act which ran counter to the government's argument, such as the use of the term "enforceable EU rights".
8. The court accepted the claimants' argument that:
(i) the government cannot change UK domestic law and nullify rights under the law unless Parliament has conferred authority upon it (the government) to do so, either expressly or by necessary implication;
(ii) the 1972 Act conferred no such authority on the government; and
(iii) the government cannot use prerogative power so as to take away the rights of citizens.
9. The government (rightly, the court said) did not contend that the Referendum Act 2015 supplied a statutory power for it to give notice under Article 50. The court stated that:
(i) unless very clear language to the contrary is used, a referendum on any topic is only advisory for the lawmakers in Parliament. No such language was used in the 2015 Act;
(ii) Parliament must have appreciated that the June 2016 referendum was intended to be advisory only, as the result of a vote in favour of leaving the EU would inevitably leave for future decision many important questions relating to the legal implementation of withdrawal from the EU.
10. The High Court therefore concluded that the UK government has no prerogative power to effect a withdrawal from the EU treaties by giving notice under Article 50.
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