In 1776, the great British economist Adam Smith wrote the following passage in his masterpiece, the Wealth of Nations:
But the annual revenue of every society is always precisely equal to the exchangeable value of the whole annual produce of its industry, or rather is precisely the same thing with that exchangeable value. As every individual, therefore, endeavours as much as he can both to employ his capital in the support of domestic industry, and so to direct that industry that its produce may be of the greatest value, every individual necessarily labours to render the annual revenue of the society as great as he can. He generally, indeed, neither intends to promote the public interest, nor knows how much he is promoting it. By preferring the support of domestic to that of foreign industry, he intends only his own security; and by directing that industry in such a manner as its produce may be of the greatest value, he intends only his own gain, and he is in this, as in many other cases, led by an invisible hand to promote an end which was no part of his intention. Nor is it always the worse for the society that it was not part of it. By pursuing his own interest he frequently promotes that of the society more effectually than when he really intends to promote it. I have never known much good done by those who affected to trade for the public good. It is an affectation, indeed, not very common among merchants, and very few words need be employed in dissuading them from it.
So we come to Brexit. It's two years since the referendum where Brits voted to Leave the EU, and 14 months since Article 50 was triggered giving formal notice to exit the EU by March 29th 2019.
The UK govt has been locked in a brutal negotiation with the EU on how to handle Brexit. The EU is determined to somehow force the UK to remain in the Single Market even after leaving, to ensure that Britain does not make trade deals with other countries and continues to accept free movement of people. The British govt is equally determined not to agree to this, spurred on by a population saying No to further immigration, and telling the govt to "get on with it".
From time to time the EU releases apocalyptic predictions of what will happen to Britain if it's government continues to be stuborn. There won't be food on the shelves. Planes will cease to fly and Brits won't be able to go on holiday to Spain! Entire industries will be lain to waste. Britain will suffer for defying the might of the EU.
Yet all the while, Adam Smith's invisible hand is working overtime.
Lots of large businesses hate the idea of Brexit because it is inconvenient for them. They also know it is futile to resist it (Britain is fond of honouring plebiscites unlike other Europeans). And - most important of all - they want to go on making money.
So in their own self-interest, just as Adam Smith predicted, they are making plans.
Today we got news that the pharmaceutical giant Merck, conscious that Britain might crash out of the EU in 2019 with No Deal, has decided to handle Brexit by revising trade routes and stockiling six months worth of goods in Britain, just in case there are delays at the ports. They've also asked customers to take two months stock in advance.
I expect other companies are doing something similar: unravelling just-in-time and building warehouses to hold goods, so that the customer notices no difference.
Meanwhile the Bank of Spain reported that Spanish exports to the UK fell in 2017 for the first time in five years. Spain exports mainly fresh fruit and veg - so the drop is likely down to British supermarkets changing their suppliers to UK ones, again to avoid possible chokepoints at the ports due to Brexit.
Pretty much every business worth it's salt is doing the same - which means that if we reach 2019 without a deal (as looks increasingly likely), life will just carry on, to the surprise of the doomsayers.
In a way Brexit is very much like the Millenium Bug - a known event happening at a known time, which you can prepare for. These types of events rarely cause recessions. Recessions are caused by unknown unplanned for events blowing up (like the unexpected collapse of Lehman Brothers).