We have continued to trade with countries outside the Union - we fill our shops with goods from Third World Countries whose slave-labour conditions benefit us
You choose to ignore the fact that Trump's tariffs are likely to effect Britain as adversely as they are anybody else
In Europe, we can negotiate on tariffs - try negotiating with Don the demic dope-head

We buy food from third world countries at prices which are artificially inflated by the tariffs imposed by the EU.
"Trump's tariffs" will affect Britain. Yes, they already do, and will do so whether or not we are part of EU. But if they were imposed to punish EU (they weren't imposed on Australia) then maybe we could negotiate different treatment if we were not part of the EU.