Approach of the European Union (Withdrawal Agreement) Act
The UK has a dualist legal system, in which an international treaty ratified by the Government, although binding in international law, does not alter the laws of the state unless and until the treaty is incorporated into domestic law by legislation. This means that the UK Parliament has to pass implementing legislation before an international treaty can have effect domestically.1 This is a necessary step in the process of ratifying the Withdrawal Agreement as an international treaty.
	The principal purpose of the Act is to implement the Withdrawal Agreement, the separation agreement between the UK and the EEA EFTA countries (EEA EFTA Separation Agreement) and the Swiss Citizens’ Rights Agreement (together, ‘the Agreements’). Where provisions of the Withdrawal Agreement (or EU law made applicable by it) are capable of having direct effect, the Act enables legal or natural persons to rely directly on those provisions in UK courts. The Act provides for these three Agreements to have an equivalent legal effect in domestic law.
	The Act is designed to work in conjunction with the EU (Withdrawal) Act 2018. Provisions relating to citizens’ rights and the financial settlement will remain separate to that Act, but the implementation of other parts of the Withdrawal Agreement and the additional commitments will require amendments to the Act. Specifically, the Act will amend the EU (Withdrawal) Act 2018 in order to give effect to the implementation period following the repeal of the European Communities Act 1972 (ECA) in section 1 of that Act. This will ensure that sections 2 to 4 of the EU (Withdrawal) Act 2018 will save, and incorporate into domestic law, that EU law which applied in the UK at the end of the implementation period – a date referred to in the Act as ‘IP completion day’. This law will then be subject to any changes made by the UK Parliament or the devolved legislatures, consistent with the UK’s international obligations. It will also be necessary to amend the EU (Withdrawal) Act 2018 to:
	a. insert the sections directly applying the Agreements (sections 5 and 6) and also to insert the rules of interpretation that will apply to ‘relevant separation agreement law’ (section 26);
	b. insert the sections which make provision for giving further domestic legislative effect via secondary legislation to provisions of the Agreements that rely explicitly on sections 5 and 6, namely the provisions giving effect to the Other Separation Issues (as defined below) and the Northern Ireland Protocol.