Much of the current narrative regarding the Brexit negotiations goes something like this: “Brexit is likely to damage the economy in the short term. Even its advocates accept that. They said that even if there is a good free trade deal with the EU we should expect the economy to take a few years to adjust, sacrificing perhaps two or three percent of GDP growth in the process. Now, they hope to get that back over the medium to longer term — Gerard Lyons talked during the Referendum campaign of a ‘Nike tick’ effect. But only a small set of economists, even amongst those that favoured Brexit, denied there would be short-term losses even if we do a good free trade deal with the EU. “Well, then, if even a deal leads to short-term losses, how much worse must it be going to be in the short-term if there is no deal? That surely must be very bad indeed! Perhaps it could be so bad that it would undermine the Conservatives’ reputation for macroeconomic management, ushering in a Corbyn government in 2022?” I think it is fair to say that some version of this narrative is near-universal. Even those keenest on no-deal are largely arguing that although no-deal is worse than the best sort of free trade agreement, at least in the short-term, that is worth doing through some combination of political gains and not sending the EU £40-odd billion we don’t owe them. I think everyone’s wrong here, and I want to explain to you why. A good free trade agreement (something like a Canada+ deal) would be the best outcome for the UK economy over the longer-term — indeed, I cannot believe anything other than a Canada+ type Free Trade Agreement is sustainable for more than a few years. And if we do do a Canada+ deal, then I agree with those that say they expect the short-term impacts on GDP to be negative — we’ll sacrifice 2 percent or so of GDP growth by around 2022. So, a deal is better than no-deal over the longer-term, and a deal will mean a short-term loss of GDP growth. But where the discussion goes wrong is in assuming that no-deal means bigger losses of GDP in the short-term. What would actually happen is (after we got through the first few weeks, say one quarter, of disruption, which might well include a non-trivial dip in GDP), GDP would grow faster in the short-term (say, the following 12-18 months) than if there had been a deal. Just because no-deal is undesirable for the economy in the longer term, it does not follow that that means we make bigger short-term losses. Let me explain why. Let’s step through some of what will happen in the economy, once we leave the EU, and compare how that plays out in the event of a deal versus no-deal. First, let’s list some of the effects there will be, as per the following table. We can see various ways UK imports will be affected, but it should be pretty uncontroversial that increased barriers to imports from the EU post-Brexit will mean fewer imports into the UK, at least in the short-term, as more of UK demand will be met by UK firms and less by EU-based firms exporting into the UK. Over the longer term, perhaps we will do more trade deals with non-EU countries or unilaterally strip away barriers to non-EU trade, and imports will end up unchanged or even higher. But in the short-term, it’s pretty clear we should expect imports to drop. It should also be pretty clear that in the event of no-deal, we’d expect imports to drop by more than if there is a deal. Again, it should be pretty uncontroversial that Brexit will mean fewer exports to the EU, and probably fewer exports overall in the short-term, and that the impact will be larger if there is no deal than if there is a deal. So, fewer imports and fewer exports, in the short term. Which effect will be bigger? Well, the UK is a larger net importer from the EU. We import about €4 worth of goods and services for every €3 we export. So if barriers to exporting and importing are fairly similar (as UK policy-makers would surely ensure they would be in most areas), the expected net impact will surely be a larger drop in imports than exports. So from this source, we’d expect a short-term boost to GDP, as net imports fell and the UK’s trade deficit improved. Next, let’s consider capital flows. There is a great deal of press discussion of UK finance firms or car manufacturers relocating some activity into the EU to avoid barriers to trade. Perhaps there will be some of that (though so far it seems to be mainly talk), but even so, that is part of that €3 of exports going out. What we do not hear about are all the EU-based firms that would relocate activities into the UK to avoid barriers. Since there are €4 of those for every €3 coming in, we should expect that more EU-based activity has an incentive to relocate into the UK than in the opposite direction. This is not quite so unambiguous as the imports/exports effect. Some firms exporting to the UK will also export to other EU markets and may face economies of scale losses in relocating into the UK, and it is arguable that economies of scale impacts may more often tend to affect EU-based than UK-based producers’ relocation decisions. So there is some interplay between inward flows, reduced imports and domestic investment. But the difference between €4 of exports and €3 of imports is so large that we should probably expect the effect to be positive nonetheless. And we should expect net inflows to be bigger if there is no deal than otherwise. Next, effects on consumption. These depend upon whether consumers expect the long-term impacts to be positive or negative for GDP, and the extent to which they react to that in the short term. This one is difficult to call. I would guess there would be little change in the event of a deal and a slight drop in the event of a no-deal. Last, domestic investment. This includes firms whose investment plans have depended upon our relationship with the EU that will do less investment or even liquidate investment. It also includes firms whose plans depend upon expansions in UK or non-EU activity. I believe it is natural to imagine that, even if the net impact on domestic investment is fairly balanced over the medium term, that will consist of a drop in domestic investment initially, as EU-dependent projects are cut back or liquidated, and the capital then only later being re-allocated to new UK-based or non-EU projects. That drop in EU-dependent domestic investment is the main reason I expect there to be slower GDP growth in the event of a deal being done. If there is a deal, I’d expect fairly modest impacts on imports and exports in the short-term, and relatively modest short-term changes to capital flows, so the drop-off in domestic investment will probably be the dominant short-term impact, meaning slower GDP growth. But if there is no deal, these other short-term impacts will be larger. Net imports will fall much more and there will be much larger inward and outward capital flows. So if there is no deal, I would expect those effects to dominate, outweighing the drop in domestic investment in the short run. Overall, what does that mean? It means that, even though we should expect slower GDP growth in the event of a deal, and even though a deal is better for the economy over the medium term than no deal, if there is no deal then in the short-term we should expect GDP to grow faster, not slower. I emphasise again that this would be after the first few weeks of drop-off in GDP associated with no-deal disruption. But it would be more than simple catch-up from disruption. It is a reflection of the basic dilemma that net importing countries always face. Free trade is good for economies over the medium to long term, but if a country is a net importer then it tends to gain output, in the short-term, in protectionist scenarios with greater trade barriers. There is no good reason to believe that this long-established basic economic truth should not be expected to apply to the UK in the case of Brexit as well.