It seems, like Levine and McCain you totally ignore the repeated testimony by Apple that the sales occur in the various countries in Europe where the appropriate taxes are paid on those profits. The net proceeds are then transferred to Ireland.
What part of 'the income has already been taxed' are you missing? Do you think countries like Britain would allow Apple UK to collect revenues from sales tax free?
You've misinterpreted what happens, I think Tim Cook was quite disingenuous about this.
Apple Operations International (Ireland) buys iPhones from Apple, or Foxconn in China at cost. Apple Operations International then sells those iPhones to Apple UK, Apple Germany, Apple France etc for close to the retail price. The local Apple Incs then sell the iphones to consumer or carriers. The local Apple Incs will pay sales tax, will have some staffing so will pay payroll taxes, but the amount of profit they book for selling iPhones will be absolutely minimal, and corporate tax for the local Apple Inc will also be minimal.
Apple Operations International meanwhile books Scrooge McDuck level of profit, since they sold the iPhones for so much more than they bought them, when it actually hasn't done anything in the real world. The iPhones were shipped from Foxconn to the local Apple Incs, AOI had no hand in anything except as a nebulous "owner" of the products for a short while. They have no staff, they have no overheads, and since through a curiosity of Irish Law they aren't "controlled" from within Ireland, they don't have to pay any corporation tax there.
Apple as a holistic entity has pretty much avoided paying any corporation tax in the EU. And it's entirely legal, which is why Tim cook is able to say that Apple pays all of its tax obligations with a straight face.
In answer to your question about whether Britain would allow this, Britain is basically king of the hill when it comes to allowing tax haven abuse. This country sold out to multinationals many years ago. Yes, we would allow this, we are allowing this, and under current policy directions it looks like it's only going to get worse.
*Obviously where I've said iPhones in the narrative above, you can take it to mean any Apple hardware product.