Originally Posted by YVR Cockroach
Here's a question: If U.K. residents were to buy over the duty/excise tax-free allowance in some non-E.U. country and come back to the U.K. via, say AMS or FRA, can they use the Blue channel safely?
It doesn't matter what you bring back from a non-EU country, if your journey originated outside the EU then you go through the red or green channel, not the blue one.
As for the exceptions... the main point I was trying to make is that Schengen has nothing to do with customs and that as far as customs control is concerned travelling to Italy from the UK comes under exactly the same rule as travelling to Italy from Germany or France. The question of whether or not a country is part of Schengen is relevant for immigration controls but not for customs.