Fair enough, so actually what the government spends your taxes on is irrelevant to your choice not to donate money to charity 
Well it shoud be - unless you have some strange idea, like Nick does, that it's all somehow going to benefit scroungers and not paying valuable people like nurses, policemen and prison warders.
No, I don't have that idea at all. I find it very odd that people feel the need to justify or whitewash the decision not to give to charity they will trot out the argument "I pay my taxes, so I don't need to"
Fine if they don't want to give money to charity, but why not just say so? No need to act like paying tax is altruistic and paying higher rate tax is the same as donating extra money to charity.