This Insight refers to the previous European Union (Withdrawal Agreement) Bill (October 2019). It does not relate to the bill presented to Parliament on 19 December 2019. Readers should be aware that there are significant differences between the two bills 

For much of the UK’s time as an EU Member State, the legal relationship between EU law and domestic law has been a controversial one. For many, it represents a constraint (in practice if not strictly in law) on the constitutional principle that the Crown-in-Parliament is sovereign. 

Against that background, the European Union (Withdrawal Agreement) Bill (WAB) includes several provisions which have major implications for what sovereignty means in the United Kingdom. 

This Insight explains: 

  • the status EU law has in UK law now 
  • what domestic status is given to the Withdrawal Agreement (and related separation agreements) and the extent to which this differs from the current status of EU law, and 
  • the legal effect of the WAB’s clauses concerned with Parliamentary sovereignty. 

Current status of EU law 

At the moment, section 2(1) of the European Communities Act 1972 (ECA) provides: 

  1. All such rights, powers, liabilities, obligations and restrictions from time to time created or arising by or under the Treaties, and all such remedies and procedures from time to time provided for by or under the Treaties, as in accordance with the Treaties are without further enactment to be given legal effect or used in the United Kingdom shall be recognised and available in law, and be enforced, allowed and followed accordingly; and the expression “enforceable EU right” and similar expressions shall be read as referring to one to which this subsection applies. 

Section 2(4) goes further and states that:

  1. … any enactment passed or to be passed, other than one contained in this part of this Act, shall be construed and have effect subject to the foregoing provisions of this section; but, except as may be provided by any Act passed after this Act… 

These are the domestic provisions that recognise, and give domestic effect to, both the supremacy and the direct effect of EU law. 

There is a broader debate about whether this relationship fundamentally restricts or subverts Parliamentary sovereignty. This led to the passage of section 18 of the European Union Act 2011, which clarifies that these ‘limits’ on sovereignty are only at Parliament’s own behest and that they can, if explicitly provided, be revoked. That section provides: 

‘Directly applicable or directly effective EU law… falls to be recognised and available in law in the United Kingdom only by virtue of that Act or where it is required to be recognised and available in law by virtue of any other Act.’ 

In its February 2017 white paper, the Government said of Parliament’s relationship with the EU: 

‘The sovereignty of Parliament is a fundamental principle of the UK constitution. Whilst Parliament has remained sovereign throughout our membership of the EU, it has not always felt like that. The extent of EU activity relevant to the UK can be demonstrated by the fact that 1,056 EU-related documents were deposited for parliamentary scrutiny in 2016. These include proposals for EU Directives, Regulations, Decisions and Recommendations, as well as Commission delegated acts, and other documents such as Commission Communications, Reports and Opinions submitted to the Council, Court of Auditors Reports and more.’

Impact of the current Bill 

In anticipation of EU exit, the Government repealed the ECA effective on ‘exit day’ (currently 31 October 2019) using section 1 of the European Union (Withdrawal) Act 2018. However the WAB ‘preserves the effect of’ the ECA until the end of transition, since the UK will (mostly) follow EU law until at least the end of 2020. We cover these arrangements in another Insight

The Withdrawal Agreement, however, has commitments on the part of the UK well beyond the transition period, some having implications for decades into the future, especially in areas like citizens’ rights. For example, the Court of Justice of the European Union is to have jurisdiction to hear cases for up to 8 years after transition and certain rights will last for the lifetime of anyone who has accrued them. 

Article 4 of the Withdrawal Agreement requires the UK to ensure that directly applicable provisions of the treaty (and anything done under it) are given ‘the same legal effects’ in UK law as they would have in EU law and in the law of Member States. It says: 

  1. The provisions of this Agreement and the provisions of Union law made applicable by this Agreement shall produce in respect of and in the United Kingdom the same legal effects as those which they produce within the Union and its Member States. Accordingly, legal or natural persons shall in particular be able to rely directly on the provisions contained or referred to in this Agreement which meet the conditions for direct effect under Union law. 
  2. The United Kingdom shall ensure compliance with paragraph 1, including as regards the required powers of its judicial and administrative authorities to disapply inconsistent or incompatible domestic provisions, through domestic primary legislation. 

Clause 5 of the Bill gives effect to Article 4. It inserts a new section 7A into the EU (Withdrawal) Act 2018. It says: 

(1) Subsection (2) applies to— 

(a) all such rights, powers, liabilities, obligations and restrictions from time to time created or arising by or under the withdrawal agreement, and

(b) all such remedies and procedures from time to time provided for by or under the withdrawal agreement,

as in accordance with the withdrawal agreement are without further enactment to be given legal effect or used in the United Kingdom.

(2) The rights, powers, liabilities, obligations, restrictions, remedies and procedures concerned are to be—

(a) recognised and available in domestic law, and

(b) enforced, allowed and followed accordingly.

(3) Every enactment (including an enactment contained in this Act) is to be read and has effect subject to subsection (2).

(4) This section does not apply in relation to Part 4 of the withdrawal agreement (for which see sections 1A, 1B and 8A and Part 1A of Schedule 2).

(5) See also (among other things)—

(a) Part 3 of the European Union (Withdrawal Agreement) Act 2019 (further provision about citizens’ rights),

(b) section 20 of that Act (financial provision),

(c) section 7C of this Act (interpretation of law relating to withdrawal agreement etc.),

(d) section 8B of this Act (power in connection with certain other separation issues),

(e) section 8C of this Act (power in connection with the Protocol on Ireland/Northern Ireland in withdrawal agreement), and

(f) Parts 1B and 1C of Schedule 2 to this Act (powers involving devolved authorities in connection with certain other separation issues and the Ireland/Northern Ireland Protocol)

Clause 5 is, for almost all practical purposes, the Withdrawal Agreement’s equivalent of subsections 2(1) and (4) of the ECA. This gives supremacy and direct effect to the relevant provisions of the Withdrawal Agreement (and any EU law rendered applicable to the UK by the Withdrawal Agreement) in much the same way as the EU Treaties are granted supremacy and have direct effect now. 

The UK Government has also negotiated agreements with the EEA, EFTA and Swiss in connection with its withdrawal from the European Union. Clause 6 of the Bill gives the same status to those agreements as clause 5 does to the Withdrawal Agreement itself. 

The Bill also includes a clause specifically about Parliamentary sovereignty. Clause 36 states that ‘it is recognised that the Parliament of the United Kingdom is sovereign’ despite clauses 1, 5 and 6 of the WAB, and that nothing in the Act ‘derogates’ from this sovereignty. 


The Bill relies on Article 4 and clause 5 doing a great deal of ‘heavy-lifting’ to implement the Withdrawal Agreement. This means the Bill dynamically tracks the Withdrawal Agreement and any EU law it co-opts, much like the ECA did. Without this provision, the WAB would have been a more complicated piece of legislation, and Parliament likely would have had to legislate frequently thereafter to “update” domestic law, to ensure ongoing compliance with the Withdrawal Agreement. However clause 5 also, therefore, replicates the kinds of restriction on Parliamentary sovereignty that the ECA and EU membership currently impose. 

There are key differences in other respects. After transition, for example, the Withdrawal Agreement only provides limited circumstances in which a UK court can make a preliminary reference to the Court of Justice of the European Union. However, clauses 5 and 6 have the effect of overriding the (otherwise) absolute rule set out in section 6(1) of the European Union (Withdrawal) Act 2018. It had provided that: 

  1. A court or tribunal—
  2. (a) is not bound by any principles laid down, or any decisions made, on or after exit day [n.b. will say ‘IP completion day’ if the Bill passes] by the European Court, and
  3. (b) cannot refer any matter to the European Court on or after exit day.

Clause 36 on Parliamentary sovereignty is of doubtful legal significance. Mike Gordon, Professor of Constitutional Law at the University of Liverpool, for example, has said in a piece for the UK Constitutional Law Association that ‘it is difficult to see that it has any practical effect in terms of diminishing the actual legal status of the obligations flowing from the Withdrawal Agreement in domestic law’. The use of the phrase ‘it is recognised’ in the clause, for example, suggests this is a political statement about the UK’s constitutional norms rather than a new justiciable rule. In 2017, the UK Supreme Court in R (Miller) v Secretary of State for Exiting the EU considered the meaning of the phrase ‘it is recognised’ in a statutory provision. It concluded that the articulation of the Sewel convention (in the Scotland Act 2016) served only to acknowledge an existing constitutional norm, rather than to elevate its status to a new legal rule. 

In its Legislative Consent Memorandum on the WAB, the Scottish Government has cast doubt on whether clause 36 is even a true reflection of the UK’s constitutional norms. It points to the territorial differences of constitutional tradition in the UK, and the role of both EU law and human rights law, as having conditioned an absolutist account of Parliamentary sovereignty: 

‘The Scottish Government considers that clause 36 does not, as it purports to do, recognise a widely-accepted principle. Instead, it represents a contested conception of the constitution, and fails to respect the different constitutional traditions that apply in and between the nations of the United Kingdom.’

About the author: Graeme Cowie is a Senior Library Clerk at the House of Commons Library, specialising in Brexit.