If you believe that voting for a Labour Government in the UK next month is going to even start changing Global Poverty ( and I agree with you ) quite simply it won't.
If you believe that voting for a Labour Government in the UK next month is going to reduce the number of people in the UK who are officially living in poverty and homeless, then go ahead and do it. In my experience Labour are actually no better than the Tories when it comes to tackling homelessness and poverty, but maybe this one would break the mould as it's way more left-centric than previous Labour Governments would ever dare to admit or claim.
All political opinion and allegiance is just that. Opinion and allegiance. It really doesn't matter what any of us on here come up with, not one of us would ever be persuaded to change our opinion and allegiance based on what someone else has posted.
It's a whole area of Tax Law called Transfer Pricing. And there's a whole industry of Tax Lawyers and Tax Accountants who specialise in it.
Without it, most multi-nationals would, as you say, peddle inferior products outside their own country of incorporation or simply cease to operate outside those countries. Which would be of no benefit to anyone in the UK if medical drugs made in, say, Germany or Belgium weren't available in the UK because it wasn't profitable for the manufacturer to export them to the UK. So what can and cannot be included in, say, the Tax Deductable costs of, say, Pfizer UK, are its contributions to such things as Pfizer's global R&D spend which might be zero in the UK but without which there would be no Pfizer UK ; Pfizer's global Marketing spend ; establishing and maintaining Pfizer's global Patents and Trademarks ; contribution to the QA systems in the Pfizer factory making the drugs if this is outside the UK; contribution to Pfizer's own Corporate functions in the Corporate HQ in New York. And there are probably quite a few more unique to Pfizer UK.
There's nothing wrong in including some of these costs in the Tax Computation for Pfizer UK - it ensures that cash does, in fact, find its way back to other Pfizer companies outside the UK which, as you say, do the R&D, Marketing, QA, etc, where the costs are actually incurred.
The local Tax Authorities' job is to agree how many of these different types of costs which are not incurred in the UK and how much by value can be claimed by Pfizer UK when calculating Pfizer UK's Taxable Profit. Unfortunately, it seems that there are now too many ' allowable ' non-local costs which are being included in Transfer Pricing these days, around the world, not just the UK, and which allow the Amazons, Starbucks, Googles of the world to take the piss.
Revenue Taxes, such as we have here, are the first step in the fight back against the piss taking.