Simple solutions to be preferred?

Should we get rid of the 50% income tax rate - which was only ever meant to be a temporary measure?  Yes, I think we should - indeed I don't think it should ever have been introduced.  I was never fortunate enough to earn enough to get into the higher (40%) tax bracket, but I have always been unable to understand the logic of having different tax rates.  The idea that the more you earn, the more you should pay in tax seems pretty obvious and equitable, but the idea that the more you earn the greater proportion of what you earn you should pay in tax has always struck me as logically dubious. Among other things it means that the more you earn the less incentive you have to earn yet more, and where's the sense in that?  Indeed the same argument can be levelled against the idea of personal tax-free allowances.  The cleanest, simplest, most equitable tax system would be one where there is one tax rate which applies to everything you earn.  Everybody keeps, and everybody pays the same proportion of what they earn.  As a by-product, think of all the money we would save in administrative costs!