"AFTER Britain’s momentous vote on June 23rd to leave the EU, many in Brussels and London want to know how it will be implemented. Since the Lisbon treaty came into force in 2009 there has been only one legal mechanism: the country that wants to leave must invoke Article 50, which sets out how it happens.
Under Article 50 it is for the other 27 countries to decide, by majority vote and without British participation, the terms of Britain’s exit. The article sets a two-year deadline for this process, which can be extended only by unanimous agreement of all 27 countries. If no deal is agreed in that time, Britain would cease to be an EU member and revert to trading with the EU on normal World Trade Organisation rules.
Brexiteers dislike this procedure as it tips the negotiating balance in favour of the EU, not Britain. Some have suggested instead another mechanism, such as a parliamentary vote to repeal the 1972 European Communities Act, which gives effect to EU law in Britain. But any such unilateral action would be illegal under both international and European law. So eventually Article 50 will have to be invoked. Yet that is unlikely to be done by the current prime minister, David Cameron, as he is resigning. It will be for his successor, who is likely to be chosen only in late September, to decide when to invoke Article 50.
Once that is done, there will also be negotiations over Britain’s new trade relationship with the EU. Because these are likely to take more than two years, they will be handled as a separate but parallel set of talks. And the new rules for trade will also have to be approved by all 27 remaining EU members and ratified by their national parliaments (and the European Parliament). That process could take many months: the EU-Canada trade deal agreed two year ago still has not been ratified. The next two years are going to be very busy."
Conclui o articulista que os próximos dois anos serão de negociações intensas ente o Reino Unido e a União Europeia, que decide por maioria de voto dos restantes 27 membros sem participação do Reino Unido. 

Entretanto, Alemanha, França e Itália decidiram hoje (a UE enquanto não for uma federação mínima terá de ser governada por um directório) que não haverá início de conversações enquanto não for formaliza pelo Reino Unido a decisão de saída.

De qualquer modo, as questões de índole económica e financeira serão, com mais ou menos tempo, ultrapassadas e concluídos os tratados que, mudando alguma coisa, deixarão o fundamental na mesma. O Reino Unido foi sempre um membro da União Europeia a meio corpo e os empresários sabem sempre descortinar por onde passam os seus interesses.

Pelo menos tão críticas no caminho da saída quanto os termos do artigo 50 do Tratado de Lisboa serão as decisões que escoceses e irlandeses do norte, manifestamente pró-UE, vierem a tomar.
Por elas, talvez a formalização da saída venha a ser adiada até ao momento em que os britânicos reconhecerem que o referendo, nos termos e na inoportunidade, foi uma imbecilidade democrática.