The following is a brief, continuously updated summary of the Brexit story, looking backwards and forwards and at where we are now ...

How we got here

A referendum on the UK's membership of the EU was announced in the government's Queen's Speech on 27 May 2015 and took place on 23 June 2016. A slim majority (51.9%) voted to leave the EU. Following a vote in Parliament, the UK notified the EU on 29 March 2017 of its intention to leave under Article 50 of the Treaty on European Unioni (TEU). This means in effect that the UK will depart on 12 April 2019 at 11pm UK time (Exit Day) unless the EU is asked, and agrees, to postpone Brexit further, or the Article 50 notice is withdrawn, cancelling Brexit altogether.

Negotiations on the UK's withdrawal initially resulted in a joint reportv, in which UK agreed among other things that there would be no "hard border" between Northern Ireland and the Republic of Ireland border after Brexit (para 49). The report was followed in February/March 2018 by a draft Withdrawal Agreement, which has now been finalised and agreed, subject to necessary political approvals (see below). This:

  • effectively extends the UK's membership of the EU to 31 December 2020 (the Transition or Implementation Period) to a date as late as the end of 2022, if need be
  • ensures a degree of continuity beyond that, to avoid a 'cliff edge' contains a 'backstop' arrangement (in a Protocol on Ireland) keeping the UK in a bare-bones customs union
  • with the EU for an indefinite period. Northern Ireland will be more closely bound to the EU, again on an indefinite basis, to ensure that no "hard border" needs to be erected in Ireland.

Subject to all this, the planned long-term relationship between the UK and EU is outlined in a (non-binding) Political Declaration accompanying the Withdrawal Agreement (together "the Withdrawal Agreement"), with the detail being left for negotiations after Exit Day.

In the meantime, the UK has passed the European Union (Withdrawal) Act 2018vi (EUWA), the main purpose of which is to copy EU law into domestic law, to the extent that the former is 'operative' in the UK before Exit Day (section 3) - or at the end of the Transition Period, if the Withdrawal Agreement is ratified and EUWA amended to take account of that (see below).

The government is also publishing a slew of Statutory Instruments to facilitate Brexit.

Where we are now

The Withdrawal Agreementvii has been agreed in principle by the UK and EU. However, it was rejected by the UK's House of Commonsviii on 15 January 2019, despite the UK Prime Minister having obtained formal assurances from the EUix regarding the temporary nature of the controversial backstop. The Labour Party immediately called a vote of no confidence in the government, which the government won the following day. Further votes of no confidence may follow.

In a vote held on 29 January 2019, the House of Commons voted in favour of the Withdrawal Agreement, subject to the backstop being "replaced with alternative arrangements to avoid a hard border". This obliged the government to attempt a renegotiation of the document. In the event, it has succeeded in negotiating supplemental documentsx which arguably change the effect of the Withdrawal Agreement, but without modifying it directly. They aim to prevent the backstop becoming a permanent arrangement. However, in a House of Commons vote on 12 March 2019 the Withdrawal Agreement was rejected again.xi A few days later John Bercow, the Speaker of the House of Commons, ruled that the Withdrawal Agreement may only be voted on again during the current session if it is changed in terms of substance.xii Since then, the government has attempted to obtain the House of Commons' approval for part of the Withdrawal Agreement - once more, without success.

On 13 March a no-deal Brexit was rejected by the House of Commons, although it remains the default position under both UK and EU law. The EU then granted a postponement: to 22 May if the current Withdrawal Agreement was approved by the House of Commons before 29 March, or to 12 April if it was not. It has now granted a further postponement - a 'flextension' obliging the UK to leave by the end of October, but also allowing it to depart earlier than that.xiii At the same time, the Prime Minister is attempting to agree with the Labour Party a way out of the current impasse.xiv If that initiative leads to nothing, further House of Commons votes on alternative plans may follow, this time organised by the government rather than backbench MPs.

If the Withdrawal Agreement is approved, a European Union (Withdrawal Agreement) Bill will need to be passed, reflecting its terms. At that point the Withdrawal Agreement will be ratified. Other domestic legislation will also have to be passed before Exit Day, e.g. to deal with agricultural subsidies.

Meanwhile the Court of Justice of the EU has ruledxv that the UK can withdraw its Article 50 notice unilaterally and continue its membership of the EU on current terms. The government was also forced in December to disclose unfavourable legal advice from the Attorney Generalxvi concerning the backstop (he says that it might never end). Further legal advicexvii, published after the release of the supplemental documents referred to above, confirms that the legal position has not changed unless the EU acts in bad faith or fails to use best endeavours to bring the backstop to an end - something that would be difficult to demonstrate in practice.

Since the outcome of the Brexit process is uncertain, the UK, EU and foreign governments have been stepping up preparations for the alternative: a 'no-deal' Brexit - see, for example, this page of technical noticesxviii that have been issued by the UK government, and the Commission's own Contingency Action Planxix. Final UK contingency plans are being activated nowxx and the EU says that it is also ready.xxi

In practice, no-deal will involve a series of mini-deals being done with the EU and/or with national governments, before or after Exit Day. Together with unilateral contingency measures, these mini-deals should ensure that urgent practical and legal matters are taken care of in the short term, although there may be severe disruption to start with.

Where next?

If the current Withdrawal Agreement is not approved by the House of Commons but an alternative way forward can be found, that might consist of amendments to the (non-binding) Political Declaration to bring it more in line with a soft version of Brexit - something the EU will be open to in principle. A referendum might also be called, since there is time for that before the new October 2019 deadline. However, it is not clear what options the UK public would be asked to choose between.

A complicating factor is that the Labour Party may soon call another vote of no confidence in the government. If passed, the vote would not necessarily lead to an early general election. Instead, the Fixed-term Parliaments Act 2011xxii provides for a two week cooling-off period during which the existing government may be confirmed or an alternative government may be formed from current MPs. Another possibility is that the government itself will call a general election, but that would require two thirds of MPs to vote for it.xxiii

Alternatively, the Prime Minister could be forced to resign, in which case a new leader may adopt a fresh approach. The Prime Minister has already said that she will resign if her Withdrawal Agreement is accepted by the House of Commons.xxiv Now that she has agreed a six-month 'flextension' with the EU, and for the UK to participate in the European Parliament elections at the end of May, she may be forced to resign in any event.

If you need to know more ...

For key dates in the Brexit process, see our Brexit Timeline. For an overview of the Withdrawal Agreement, as well as what the alternative versions of Brexit called Norway Plus (or Common Market 2.0) and no-deal would involve, see How Brexit Works. This also explains how votes of no confidence work, and the issues surrounding a second referendum.