Now that article 50 has been triggered, what is the effect in law? This contribution considers its further provisions, including the inbuilt uncertainties over timing

Wednesday 29 March 2017 saw the beginning of the long, unprecedented and tumultuous journey to fulfil the referendum mandate delivered by the people to politicians on 23 June 2016: the United Kingdom is withdrawing from the European Union.

With a high-profile battle through the High Court and concluding with the Supreme Court’s judgment in R (Miller) v Secretary of State for Exiting the European Union [2017] UKSC 5, that parliamentary consent is required before the executive can trigger article 50 of the Treaty on European Union ([2012] OJ C 326/13), “Brexit” is a public lawyer’s dream. The legal implications and requirements of article 50, alone, should not be underestimated.

Articulating article 50

Article 50 has five subsections. Article 50(1) provides that a member state may “withdraw from the Union in accordance with its own constitutional elements”. With assistance from their Lordships’ judgment in Miller, this was enabled through June 2016’s referendum and the European Union (Notification of Withdrawal) Act 2017, which was given Royal Assent on 16 March 2017.

On 29 March, Theresa May completed the next step in the article 50 saga – the United Kingdom shall notify the European Council of its intention to withdraw from the European Union, per the requirements of article 50(2). This was in the form of a written letter delivered to the Council, followed by Mrs May providing a statement to the House of Commons informing Parliament and setting out the aims and future relationship the British Government wishes in negotiation with the European Union. European Council President, Donald Tusk, responded on the same day stating that the first step for the European Union would be the adoption of guidelines for the negotiations by the European Council.

Article 50(2) also establishes that a potential Withdrawal Agreement will be negotiated in terms of article 218(3) of the Treaty on the Functioning of the European Union ([2012] OJ C326/47) – this deals with negotiations between the EU and third parties. Any Withdrawal Agreement will be concluded by the European Council, acting by a qualified majority, and after the agreement of the European Parliament.

One myth that has stemmed from the recent attention on article 50 is the “two-year deadline” to negotiate a Withdrawal Agreement. This is not completely factual. Article 50(3) states that membership “shall cease to apply… from the date of entry into force of the withdrawal agreement or, failing that, two years after the notification… unless the European Council, in agreement with the Member State concerned, unanimously decides to extend this period”. Membership, and the EU Treaties, shall cease on the date that any negotiated Withdrawal Agreement comes into force. Article 50(3) does not stipulate that a Withdrawal Agreement must be reached within two years; only that if no agreement is reached then membership shall cease two years from the date that the withdrawal notification is issued to the Council.

UK politicians have repeatedly, and wrongly, stated that withdrawal will take two years – due to the complexity of withdrawal, this is extremely unlikely. This myth is perfectly highlighted in the Daily Telegraph’s recent article entitled “What is Article 50? The only explanation you need to read”, where it states that “The process is supposed to take two years but many people believe that it could take longer.” Article 50 is silent on the duration of withdrawal negotiations, except that if no Withdrawal Agreement is reached then membership ceases after two years. However, this can also be postponed if an agreement to extend the period of negotiation is reached between the Council and the UK.

Article 50(4) prohibits the UK from participating “in the discussions of the European Council or Council or in decisions concerning it”. This clearly establishes that a notification to withdraw from the EU, under article 50, provides a semi-transition for the UK from a member state to a third party, for the purposes of all decisions and matters relating to the withdrawal. The United Kingdom can still participate in the work of the European Union in all other areas, although it is unlikely that the UK Government will continue to participate in votes of the European Council.

Following the “termination” of the UK’s membership of the EU, if Mrs May, or any future British Government, were to follow David Cameron’s recent utterance on Arnold Schwarzenegger’s snapchat of “I’ll be back”, they could reapply for membership of the EU under article 50(5), which allows for former member states to return under article 49. However, if the UK were to reapply following withdrawal, this would not come with the current opt-outs and preferential treatment that has been provided under our current membership.

Concluding remarks

“…there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns – the ones we don't know we don't know.” (Donald Rumsfeld, 13th and 21st United States Secretary of Defense, news briefing, 12 February 2002.)

As at 29 March 2017 it was 280 days since the United Kingdom voted to leave the European Union. On that day Prime Minister Theresa May triggered article 50 of the Treaty on European Union. This, “we know we know”.


The United Kingdom will immediately begin work to negotiate a Withdrawal Agreement with the EU. However, failing an agreement on a future Withdrawal Agreement, the UK would be forced to adopt World Trade Organisation rules. It is unclear whether we are currently even a member of the WTO in our own right. Furthermore, would the a future trade deal with the EU be possible following a potentially divisive divorce? These are the “known unknowns”.


Lastly, the terms of Britain’s future: international relations, trade commitments, and jurisprudential development cannot be predicted, even amongst legal commentators. The months following the triggering of article 50 will, hopefully, shine a light on these issues, but for now… there are many “unknown unknowns”.



The Author
Andrew Agnew is a student on the Diploma in Professional Legal Practice at the University of Dundee
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