Guess it depends on whether you're talking absolutely or relatively. The EU exports more to the UK than the UK does to the EU. If we assume that, in both directions, those exports go elsewhere then as a whole lot wouldn't hurt the EU as much in relative terms, but it would cost them more greatly absolutely than it would cost the UK.
Obviously though exports are only part of the story.
Most of the UK's 'positive' trade is in services
2014: Services exports of 361 709.0 million USD vs Services imports of215 600.5 million USD
against Trade in Goods of exports of 483 629.3 million USD vs imports of 686 379.2 million USD
Trade in Goods can survive under a WTO GATT deal after all it's what we and the EU use to trade with the likes of the US and China, services would really struggle under a WTO GATS deal with the EU, GATS tends to be far more contentious and generally requires a per sector (and per contract) smooth out.
Sir David confirmed that, should the UK be forced to withdraw unilaterally
in this way, it would have no option but to fall back on the trading terms
derived from its membership of the World Trade Organization (WTO).57
Professor Wyatt told us the following consequences would be likely to ensue:
“We would impose tariffs on goods almost certainly at the same level
as the common external tariff. That is the tariff we impose to the
outside world currently. We leave the EU; we impose those tariffs on
goods coming to us. The EU would be a third country; the EU would
be imposing those tariffs on us. Of course, that would cost customers;
it would cost people in the shops. We cannot disarm in tariff terms,
because that is our ammunition in negotiating trade in goods. We also
want to negotiate trade in services, where the WTO is not very good
for us … There would be tariffs between the UK and the EU, many
of them not very high but some of them—as the Government pointed
out—would be 10% on cars and 35% on dairy products.”
That also precludes the financial services sectors need for EU financial passporting which would be off the table in the event of an unorderly exit (and frankly is off the table unless a EEA deal is concluded and even then is still questionable)
Of course in all the talk of German Car manufacturers, it's often forgotten that about 60% of Cars manufactured in the UK go to the EU, whereas just under 20% of German manufactured cars go to the UK. German car manufacturers of course have lots of specific political, emotional (yes it does exist to a point in business) and ownership related reasons (lots of German car manufacturers biggest shareholders are German municipalities) to continue car manufacture in German. In contrast all the UK car manufacturers are foreign owned and frankly if the costs are sunk have little real reason to stay if the trade situation is unfavourable to them.
The UK really doesn't have that strong a hand. Trade in Goods is workable under a WTO fallback, trade in Services not really. The UK is a large economy with a terrible trade surplus, a terrible fiscal surplus fuelled by high consumer debt and over reliance on financial services which relatively easy to move out.
This is ending up at best an EEA deal, which by any objective measure is an absolute shafting (not to mention politically disastrous; although my schadenfreude when the realisation hits leave voters will be great; I mean they might be able to sell them a reduction contribution if we get and the 'advisory' nature of the ECJ to EEA participants along with some per sector exclusion but it's a far cry from closed borders and taking back 'ma country' ), we're only negotiating how big the cock is, whether they give us a cuddle before and afterwards and a reach around during it.
