Analysis

The Article 50 process can be divided into three phases:

Phase 1

The Council, led by the head of the 'Brexit taskforce' of EU negotiators, Didier Seeuws, and the member states it represents -- without the United Kingdom -- will draw up a negotiating mandate ("guidelines") on how it intends things to play out.

Article 50 does not indicate how the guidelines will be created and adopted, or what they will contain, but it seems likely that they will take the form of a lengthy annexe to the conclusions of a special Council meeting that will be held on April 29.

The guidelines will reiterate the principles first specified in the Council's statement of June 29, 2016. The United Kingdom will be welcomed as a prospective "close partner" of the EU; any agreement will be "based on a balance of rights and obligations"; and "access to the single market requires the acceptance of all four freedoms".

The Council will probably make a reference to the hitherto neglected Article 8 of the Treaty on European Union, which reads:

• 1. "The Union shall develop a special relationship with neighbouring countries, aiming to establish an area of prosperity and good neighbourliness, founded on the values of the Union and characterised by close and peaceful relations based on cooperation."
• 2. "For the purposes of paragraph 1, the Union may conclude specific agreements with the countries concerned. These agreements may contain reciprocal rights and obligations as well as the possibility of undertaking activities jointly. Their implementation shall be the subject of periodic consultation."

The modalities of the negotiations, first broached in the conclusions of the Council meeting of December 15, will also be mentioned.

Phase 2

The European Commission's 'Article 50 taskforce' negotiating team, led by Michel Barnier and Sabine Weyand, negotiates the exit agreement with the United Kingdom on behalf of the EU.

As laid down in Article 218(3) of the Treaty on the Functioning of the European Union, the Council's guidelines will lead the Commission to make recommendations to the General Affairs Council (GAC), which will then make the formal decision to open the negotiations with the United Kingdom.

That decision will not be taken before a new French minister is appointed responsible for European affairs -- unlikely before June.

The Council will establish a special committee to monitor the progress of the Article 50 talks, and a representative of a Council working party, chaired by Seeuws, will be present at all the meetings between the Commission and the United Kingdom.

The Council will review the progress of the negotiations at each of its meetings, issuing revised guidelines as appropriate, and the GAC can be expected to address further operational directives to the Commission from time to time.

It will be up to the Commission to propose to the Council that an agreement can be concluded (Article 218(5)).

Phase 3

The deal needs to be approved by the United Kingdom and a special qualified majority of the Council: 20 of the 27 remaining states. The European Parliament also has to approve it, by a simple majority (see EU: A united front points to tough Brexit negotiations - October 31, 2016).

All of this, Article 50 states, must be concluded within two years after notification -- at which point the United Kingdom, unless it has won the unanimous agreement of the rest of the Council, or the agreement specifies an earlier or later date, will no longer be an EU member.

It is possible that a special body will have to be set up to monitor the application of the agreement, smooth the operation of the divorce settlement and settle lingering disputes -- for instance, over legacy budgetary issues -- for a certain, probably ill-defined transitional period.

Unknowns

Perhaps the most obvious issue that has not been resolved is that of what the talks will focus on and when (see EU/UNITED KINGDOM: Talks may not clarify relationship - December 7, 2016).

The UK government is determined that talks on a longer-term trade deal take place simultaneously with those on the Article 50 deal itself. However, the mood in the EU and among the remaining member states seems to be hardening in the direction of resolving the key issues related to Article 50 prior to any negotiations about the future.

This would weaken the United Kingdom's bargaining position, as the government would be under enormous time pressure to sign up to whatever Article 50 deal was on the table, in order to proceed to the next stage of the talks -- the trade deal.

Should the EU insist on sorting out the Article 50 issues -- which could mean simply what the Article 50 talks should cover or, more substantively, might deal with practical issues such as the size of any 'Brexit bill' -- May could conceivably consider walking out of the talks (see UNITED KINGDOM: May will pursue ‘hard’ Brexit - January 20, 2017).

Time constraints

Even if the UK government gets its way and the two sets of talks are carried out simultaneously rather than sequentially, it is hard to see how they could be completed within the two years allowed under Article 50.

Elections in other member states will reduce the time available for negotiations, as will the unexpected crises that are likely to occur.

Given the time necessary to ensure ratification of any deal -- several months in all likelihood -- this will only leave around 16-18 months for the talks. This will be a tight schedule to hammer out all the details of the Article 50 deal, let alone a longer-term trade deal.

It is probable, therefore, that some kind of transitional arrangement will have to be signed to ensure that the United Kingdom does not simply 'fall out' of the EU without any kind of agreement on trade (see UNITED KINGDOM/WTO: Negotiations may hit growth - September 6, 2016).