It's worth remembering that income tax represents only a quarter of all UK taxation. The rest has to be found from those other sources we're so good at complaining about (VAT, IHT, National Insurance, fuel duty et al).
Incidentally, taxes pay our (the armed forces') wages, which you might like to bear in mind, next time you're tempted to bleat about how much of your income (or inheritance) ends up with the Revenue.