Re: Ok but how much tax is fair?
Starbucks may be a particular case: for many years they were contrasted with UK-owned Costa paying their full whack of corporation tax here.
It may be instructive that Costa was recently sold to a US megacorp (Coca Cola). So in principle at least, they can now play all the same tricks as Starbucks. I don't know what happens in practice, but this is a particular case-in-point where being British-owned appears to have put Costa at a tax disadvantage compared to a major rival.