To understand Article 50 properly, though, we must go to Altiero Spinelli, father of the Maastricht Treaty and of the European Union. His concern was the Union should be seen to be a voluntary association of nations, which it could not be as long as there was no exit clause.
Famously, he said that European Union should not be a prison, and when he drew up his Draft European Constitution for the European Parliament in 1984, he included in it an exit clause.
This was taken up during the Constitutional Conventions, proposed, incidentally by Frenchman Michael Barnier, and thence to the Lisbon Treaty where it became the current Article.
Far from being a “trap”, therefore, as some will aver, Article 50 is a genuine exit clause, necessary for the EU’s own image of itself. Needless to say, they think that their Union is so wonderful that no-one would want to leave it – as did Spinelli – but that is another story.