The European Union (Withdrawal) (No. 2) Act 2019 became law on 9 September 2019, imposing a legal obligation on the Prime Minister to request a third extension to the Article 50 period until 31 January 2020 unless, by 19 October 2019, the government has obtained Parliament’s consent either to a withdrawal agreement or to a no-deal exit.
The new Act requires the Prime Minister to immediately accept any European Council decision to agree an extension to 11.00 pm on 31 January 2020. If the European Council proposes a different end date, the Prime Minister must either accept that extension, or ask the House of Commons whether it approves the proposal. If the House of Commons decides not to pass a motion approving the proposed extension, the Prime Minister can then choose to accept or reject the proposal.
The Act thus amends section 20(4) of the European Union (Withdrawal) Act 2018 (EUWA) to impose an express obligation on the government to make any amending regulations required to change the EUWA definition of exit day, by changing “may” to “must”.
If, by the time an extension period starts, the exit day definition is not changed to reflect the new exit date, the extension still has effect (the UK would remain an EU member state throughout the extension period), but the UK would be in breach of its international obligations to give effect to EU law in domestic law during that period. If exit day is not changed, domestic legislative events would be triggered on the old exit day (as defined in the EUWA) that would be incompatible with the UK’s position as a continuing member state during the extension period, such as the repeal of the European Communities Act 1972 and the creation of Retained EU law as UK law.