Next steps after Britain pulls Brexit trigger

When British Prime Minister Theresa May triggers Article 50 of the EU's treaties, it will start a difficult two-year Brexit negotiation process.

Actual talks between London and Brussels are not expected for another couple of months while the European Union side formalises its position.

Here are the key steps ahead:

European Council President Donald Tusk has said he will issue draft "negotiating guidelines" within 48 hours of Article 50 being triggered. These are overall political red lines for the next two years and will be circulated to the capitals of the 27 remaining EU countries.

Diplomats will start preparing for an extraordinary summit.

The leaders of the 27 will hold a special Brexit summit in Brussels to approve the negotiating guidelines.

The summit is expected to be in late April or early May, if May triggers Article 50 as expected at the end of March.

The guidelines will have a broad political message "but you could probably write them yourself," as they cover much of what leaders have already been saying for months, a European diplomat told AFP.

Within 24 hours of the summit at 27, the European Commission, the executive arm of the EU, will make its first formal reaction to the start of the Brexit process -- issuing an initial "Recommendation to Open Negotiations".

The EU 27's European affairs ministers, meeting in the so-called General Affairs Council, will meet to draw up the "Negotiating Directives" in the weeks after the summit.

These are much more detailed than the EU 27's negotiating guidelines, going into the "nitty gritty" of Brexit, and will largely be based on the Commission's recommendation to open negotiations.

The directives will include the three key issues which the EU wants to deal with first, preferably this year: the departure bill Britain will have to pay; the rights of EU citizens in Britain; and the flashpoint border in Northern Ireland.

Between six and eight weeks after London triggers the process, the EU ministers will approve the negotiating directives and formally give the European Commission's chief Brexit negotiator, Michel Barnier, the mandate to start negotiations.

This is when the Britain-EU talks actually begin.

It is expected in late May to early June -- nearly a year after Britain's referendum vote to leave the bloc.

Barnier's talks with the British will be officially be governed by both documents -- the negotiating guidelines from the EU 27 national leaders, and the detailed negotiating directives.

Barnier and Britain must also work out practical issues such as what language the talks will be held in -- Barnier is French -- and the timetable, though some of those issues may be sorted out earlier.

"There's nothing to stop us talking about procedure before we get the mandate as long as we are not actually negotiating," one diplomat said.

The EU says it will only discuss Britain's future relationship, including a possible trade deal after the leaving bill, citizens rights and Northern Ireland are resolved.

Britain however says they can start in tandem with the initial three key issues. Whatever happens, the aim is to discuss the broader future in 2017 to 2018.

Barnier has set October 2018 as the latest feasible date for a draft Brexit deal to give it time to be approved by the British parliament, by EU leaders and by the European Parliament, which will have the final say.

Britain will formally leave the EU two years after the notification of Article 50 -- with or without a deal. In theory negotiations can be extended but the EU 27 are unlikely to agree. European Parliament elections are expected in June 2019.

It is still unclear today whether Britain can annul the Brexit process before the deadline if it changes its mind; and whether the final deal, as well as extension of talks or a transitional accord, also has to be approved by all of the parliaments in the EU states.

Even if Britain does manage to make a deal with the EU, the accord is likely to be partial or transitional.

A full deal for the future relationship will probably take years -- up to seven years according to Tusk, or even a decade, according to reported comments by Britain's former ambassador to the EU.

- AFP