Article 50 of the Treaty on European Union provides that any Member State may decide to withdraw from the EU in accordance with its own constitutional arrangements. It also provides that the EU and the withdrawing state shall negotiate an agreement setting out arrangements for its withdrawal. The withdrawing Member State will cease to be a member of the EU when the withdrawal agreement comes into force, or failing that, two years after notifying the EU of its intention to leave.
In the UK’s case, the notice to withdraw from the EU was issued on 29 March 2017. The UK will therefore leave the EU on 29 March 2019, unless a withdrawal agreement with the EU provides for another exit day or the UK Government withdraws the Article 50 notice or there is agreement with the EU to extend the Article 50 notice period.
The Prime Minister has been clear that she intends to deliver on the 2016 referendum result in taking the UK out of the EU, and that the Government will not revoke Article 50. She has also spoken against the possibility of extending Article 50. She has also repeatedly stated that the UK will leave the EU on 29 March 2019. The House of Commons voted to reject amendments that would have enabled an extension of Article 50 following the debate on the Government statement on the Brexit negotiations on 29 January 2019.
A Withdrawal Agreement (WA) was approved by the UK Government and EU leaders at the European Council on 25 November 2018. This provides for the UK to leave the EU on 29 March 2019, and will come into force provided it is first approved by both the UK (meaning approval by the House of Commons) and EU (requiring approval by both European Parliament and Council of the EU).
In the vote on the WA in the House of Commons on 15 January, it was defeated by 432 votes to 202. Following the debate and vote on the Government’s next steps in the Brexit process on 29 January, the Prime Minister set out her intention to seek further negotiations with the EU on the WA, in order to obtain legally binding changes to the most contentious element of the WA, the Northern Ireland/Ireland backstop, that would be acceptable to a majority in the House of Commons. The EU has indicated it is unwilling to re-open negotiations on the WA.
If the Government is unable to reach agreement with the EU on changes to the WA or on other assurances that are acceptable to the House of Commons, then the UK will leave the EU without a deal on 29 March 2019 unless there is a change in the Government position on extending or revoking Article 50.
Foreign Secretary Jeremy Hunt indicated on 31 January 2019 that an extension of Article 50 could be requested if the WA is approved shortly before 29 March, in order to provide for extra Parliamentary time to pass legislation to prepare for Brexit.