On 23 January 2020, the European Union (Withdrawal Agreement) Bill 2019-20 received Royal Assent becoming the European Union (Withdrawal Agreement) Act 2020 (the Act). Amendments made to the Bill in the House of Lords were overturned by MPs sitting in the House of Commons.

Article 126 of the Withdrawal Agreement states that there shall be a “transition or implementation period” which shall start when the agreement enters into force and end on 31 December 2020. The UK Government prefers to use the term “implementation period” or “IP” for short, while the EU uses the term “transition period” to denote the same thing.

Article 127(1) of the Withdrawal Agreement sets out the scope of the transition: “Unless otherwise provided in this agreement, [European] Union law shall be applicable to and in the United Kingdom during the transition period”. Article 127(3) specifies that during the transition period, EU law (with specified exceptions) shall produce “in respect of and in the United Kingdom the same legal effects as those which it produces within the Union and its member states”.

The European Communities Act 1972 (ECA) is the “conduit pipe” through which EU law flows into UK domestic law. Section 1 of the European Union (Withdrawal) Act 2018 (EUWA 2018) is set to repeal the ECA on exit day, 31 January 2020.

To ensure that the EU treaties and other EU law continue to apply in the UK during the implementation period, section 1 of the Act inserts a new section 1A into EUWA 2018. This allows the ECA to continue to have effect in domestic law despite being repealed, subject to certain conditions, including:

• part four of the Withdrawal Agreement (except those provisions that relate to the common foreign and security policy) is added into the definition of EU law and the EU treaties that are given effect in domestic law by the ECA; and
• section 2(3) of the ECA would not continue to apply. This is the section of the ECA that authorises payments from the UK to the EU under the EU treaties. The financial settlement that will apply after the UK has left the EU is dealt with separately in section 20 of the Act.

Subsection 1A(5) ensures that the saving of the ECA would last only until the end of the implementation period. The operative provisions of section 1A would be repealed on “IP completion day”. Section 39 of the Act defines IP completion day as 11pm on 31 December 2020. Section 26 of the Act provides that wherever ‘exit day’ appears in the EUWA 2018 it will be substituted by IP completion day.

Section 2 of the Act inserts a new section 1B into the EUWA 2018 to save EU-derived domestic legislation for the duration of the implementation period. The new section contains a number of provisions and explanations that are intended to ensure that EU-related references operate during the implementation period.

Section 3 gives UK ministers a regulation-making power to make further technical changes to ensure that the UK statute book continues to function during the implementation period. However, this power could not be used to modify primary legislation made after IP completion day, or subordinate legislation made under that primary legislation. This regulation-making power would end two years after IP completion day. Section 4 creates a corresponding power for the devolved authorities.

Section 33 of the Act inserts a new section 15A into the EUWA 2018 which prohibits a Minister of the Crown from agreeing to an extension of the implementation period.