15 August 2019 - The new Prime Minister of Britain, Boris Johnson, is one of the more strident Brexiteers. He's made it clear that while he favors reaching a deal with the E.U., a no-deal Brexit is a definite option.
Halloween looms large this year as there needs to be a deal struck by 31 October, or else Britain crashes out of the E.U. without a deal.
No member state has previously decided to leave the E.U., so there is no precedent for this situation and therefore no empirical lessons to draw from. This leaves multiple stakeholders with a great degree of uncertainty.