Correct me if I'm wrong, but Countries don't put tariffs on goods they export, they put tariffs on goods they import. The UK imports more from the EU than the EU imports from the UK. Therefore we, by that I mean our government, will get more out of the exchanges than their EU equivalents. Their goods will become more expensive over here and our exports will become more expensive over there. A short term gain for both governments and only a short term loss for those who can't be bothered to to find non taxed alternatives. Any loss of business as a result of this will be proportionate to the overall size of trade. As a result the EU losses will be greater than the UK losses. You appear to be assuming that the EU will be stupid about this and maximise rather than minimise these losses. If this is so we certainly are better off out.