Publications / Briefings

Legislating for transition / implementation: implications for the EU (Withdrawal) Bill

17 Apr 2018
UK and EU flags superimposed on top of the Houses of Parliament

The prospective post-Brexit implementation / transition period will require amendments to the European Union (Withdrawal) Bill. Some can be made by the promised Withdrawal Agreement and Implementation Bill, but some could be made before the EU (Withdrawal) Bill is passed.

In this April 2018 briefing paper, Swee Leng Harris of the Legal Education Foundation explores what the promised Withdrawal Agreement and Implementation Bill (WAI Bill) needs to do, and how the EU (Withdrawal) Bill needs to be amended, to provide for the prospective implementation / transition period.

When the EU (Withdrawal) Bill was introduced into Parliament in July 2017, an implementation / transition period was merely a possibility. Agreeing such a period reflecting the status quo was not UK Government policy until the Prime Minister’s speech in Florence in September 2017. Accordingly, it was hard to determine how the EU (Withdrawal) Bill could provide for implementation / transition until the UK and European Council agreed text on it in the draft Withdrawal Agreement on 23 March 2018.

However, now that the Withdrawal Agreement is significantly more likely, in the interests of the rule of law the government needs to provide greater clarity and certainty about the next steps in legislating for Brexit and the relationship between the provisions in the EU (Withdrawal) Bill and the proposed WAI Bill.

Without this clarity, MPs and Peers risk spending many hours in the coming weeks scrutinising legislation that will shortly need to be amended or will be superseded. More widely, individuals and businesses in the UK will not know what to expect from this Brexit legislation: how should they prepare to comply with the regulatory provisions that will flow from the EU (Withdrawal) Act if it is likely that some of them will soon be outdated and supplanted by the provisions of the WAI Bill?

The briefing paper considers what the likely scope and content of the WAI Bill will be, and what amendments are needed to the EU (Withdrawal) Bill to accommodate an implementation / transition period. It assumes that a Withdrawal Agreement will be reached between the EU and UK, and proceeds based on the available evidence of the UK and EU’s positions and intentions. Inevitably, these positions may change, and the intentions may not be achieved. An anticipated timeline of negotiations and legislation is set out in the appendix.

The paper concludes that a number of legislative changes are needed in order to accommodate an implementation / transition period. Some amendments to the EU (Withdrawal) Bill could be made after it becomes law, via provisions in the WAI Bill. But some amendments could and should be made earlier, while the EU (Withdrawal) Bill is still being scrutinised by MPs and Peers, to ensure that it is fit for purpose before it receives Royal Assent.

  • The WAI Bill will need to replicate the effect of the European Communities Act (ECA) to bring EU law into the UK for the implementation / transition period. Notably, EU law will develop and change during the implementation / transition period, and the WAI Bill will need to enable those changes in EU law to be reflected in UK law, including through amendments to delegated legislation made under the ECA.

  • The WAI Bill will also need to insert a new provision in the EU (Withdrawal) Act so that EU laws that enter into UK law through the WAI Bill form part of ‘retained EU law’.

  • ‘Exit day’ serves multiple functions in the EU (Withdrawal) Bill, and needs to be split into at least two if not more different points in time:

    • ‘repeal day’ — the beginning of the implementation / transition period when the ECA is repealed under clause 1 and regulations under that Act are saved under clause 2 (as noted above, there will need to be a power, perhaps in the WAI Bill, to update delegated legislation made under the ECA that has been saved by the EU (Withdrawal) Bill); and

    • 'retention day’ — the point in time at which EU law is retained, i.e. the ‘snapshot’ of EU law is taken under clauses 2-4, which should be the later of the day on which the UK ceases to be a member of the EU or the end of the implementation / transition period. If no transition / implementation period were agreed between the EU and UK, then ‘retention day’ will be the same day as ‘repeal day’.

  • Consequential amendments will be needed to enable retention of EU law under clauses 2 and 4 if the ECA is to be repealed on ‘repeal day’ (at the beginning of the implementation / transition period) and the snapshot of EU law to be taken on ‘retention day’ (at the end of the implementation / transition period).

  • The delegated legislative powers in clauses 7 and 8 should be amended so that they are subject to Parliament’s approval of the future EU-UK relationship.

  • Clause 9 could be repealed and replaced with a new clause providing for the next steps in the Brexit legislative process.

The views expressed in this publication are those of the author alone. The Hansard Society provides a non-partisan forum for the exchange of ideas and, in publishing this paper, aims to contribute to public knowledge and debate.

News / Parliament’s spying scandal: Why was the China case dropped? - Parliament Matters podcast, Episode 110

It’s been a tumultuous week in Westminster, with three ministerial statements on the China spying case and fresh questions about the collapse of charges against two alleged spies. We are joined by Cambridge public law expert Professor Mark Elliott to untangle the legal and political fallout, from espionage claims inside MPs’ offices to confusion over whether China was ever designated an “enemy state.” We also explore looming government challenges — the Budget, Afghan data leak, local election setbacks — and the membership of the new Select Committee to consider the assisted dying legislation in the House of Lords. Please help us by completing our Listener Survey. It will only take a few minutes.

17 Oct 2025
Read more

News / Parliament Matters Bulletin: What’s coming up in Parliament this week? 13-16 October 2025

Parliament returns this week after a three-week recess. MPs may address developments in Israel and Gaza, the collapse of the China spying case, plans for digital ID, and recent immigration announcements. They will also scrutinise four Bills, question four departmental ministerial teams, debate baby loss and badger culling, and hear evidence from tax experts, energy executives, and travel and immigration experts. In the Lords, the membership of the new Select Committee to consider the Assisted Dying Bill will be confirmed. Peers will examine six Government Bills, debate the National Policy Statement for Ports, and question the Border Security Commander. Two new Peers, Liz Lloyd and Jason Stockwood, will take their seats following their recent ministerial appointments.

12 Oct 2025
Read more

News / Former Prime Ministers: The role of Parliament in life after No 10 - Parliament Matters podcast, Episode 109

In this episode, we speak with Peter Just, author of a new book, Margaret Thatcher: Life After Downing Street. Peter explores how Thatcher reinvented herself after her departure to maintain her status as an international figure, and how she remained a parliamentary thorn in John Major’s side. We also compare her parliamentary afterlife with that of other Prime Ministers, and consider the value that former leaders can bring to the institution of Parliament. Please help us by completing our Listener Survey. It will only take a few minutes.

03 Oct 2025
Read more

Briefings / Assisted dying - The Terminally Ill Adults (End of Life) Bill: Rolling news

Stay informed with updates and analysis on the Terminally Ill Adults (End of Life) Bill as it moves through Parliament. Learn about the debates, procedures, decisions, and key milestones shaping the assisted dying legislation.

15 May 2025
Read more

News / What are the Usual Channels? A short history of Westminster whipping - Parliament Matters podcast, Episode 108

In this episode, we talk to political journalist Seb Whale about his new book, The Usual Channels, which reveals the hidden world of Westminster’s whips. Seb charts how party discipline has evolved – from the stormy politics of the 1970s and the Maastricht battles of the 1990s to the legendary “black book,” the Brexit showdowns and the short-lived Liz Truss premiership. He explains how the whips’ office has adapted to a modern Parliament – especially with the influx of women MPs – and why, even today, whips still wield decisive influence over MPs’ careers and remain indispensable despite the pressures of contemporary politics. Please help us by completing our Listener Survey. It will only take a few minutes.

26 Sep 2025
Read more