1. There are plenty of #Brexit threads kicking around now on why the WTO option is bad. Unless you live in a cave or have the IQ of a halibut, you should by now have grasped the concept of what it means to be a third country and why that is ruinous for UK exporters.
2. You'll note that in the seventeen billion threads I've written on the subject that I seldom make reference to tariffs - because tariffs for the most part are neither here nor there. This is fundamentally about regulatory barriers where again the cave/halibut question kicks in.
3. Without full regulatory harmonisation there will be inspections, standard third country controls will kick in and there are no WTO rules that compel the EU to relax them and certainly not for the sole benefit of the UK. This is why we need a comprehensive agreement with the EU