I've mentioned it before, but the tax system is far more complicated than the percentages. Every time the tax code is rewritten, ambiguous language is used in some parts so the avoidance industry (which is huge) has something to play with. Every decent accountant will have a tax advisor who specialises in finding loopholes which can save their clients money. More people are employed in tax avoidance than there are those who are avoiding the tax.
The other thing I've never understood (and I'm fairly young and not even living in the UK) is why there is so much animosity towards wealthier people, when by and large they've worked damned hard to get where they are. How many people can claim to hate the rich but at the same time remember the days when they messed around in school? Everybody has to work, that's a given, but how many of us have actually worked hard at the things that mattered when they mattered?