The result of the Salzburg EU leaders summit and the recent comment by the French minister for European affairs that a no deal Brexit will be better than a bad deal for the French, provide a great opportunity to show the member states what they will miss if we leave the EU without a deal.
As a preliminary test of how things must change, we simply stop buying goods from one of the member states. As President Macron is perhaps the most vocal opponent of the UK then we should immediately cease buying anything French.
If the French took umbrage and blockaded the channel ports then we would have to switch everything to the Dutch and Belgium ports. If the Dutch and Belgium governments then joined the French, it would not be long before the business leaders of the EU started knocking a few political heads together because such a situation will not benefit anyone least of all the EU.
If the bureaucrats in Brussels had been more receptive to the minimal and reasonable changes that David Cameron had been looking for then we would not be in this position today.