There was always a possible deadline for triggering Article 50, which is May 18th. Why? Well two years later, on May 19th 2019, it’s time for another round of European Elections. Within Article 50 there’s no specific mention of what happens if a European Parliament election occurs during the withdrawal process regarding the withdrawing member’s participation. There’s a bit of a mess brewing there. Although the UK wouldn’t participate in most EU matters during the withdrawal, their MEPs remain members of the parliament and carry on, apparently, as normal. The 73 UK seats might be reallocated amongst the other countries. Or maybe, again it’s unclear, the seats will be erased. Doing any of those things will mean a whole load of extra negotiation as part of the withdrawal agreement.
Article source: http://www.huffingtonpost.co.uk/andrew-keith-walker/article-50_b_12261272.html?utm_hp_ref=uk-politics&ir=UK+Politics