For every £10k invoice I submit, the govt gets £4738, so effectively over 47% tax (£2k VAT, £2,300 tax, £437 NI) assuming I work all year, so 12 invoices, no holiday pay, no sick pay, and no pension contributions.
That is a positive contribution - I haven't been to a GP in 5 or more years, my children are in fee-paying schools. That is earned by myself, no staff.
The problem is that when high earners receive nothing back from the system (I get no child benefit, for example) they cease to worry about the people that are gaining from the system (those that get back more than they put in). They certainly don't think they should be paying more in.
I am someone who cares about society, I believe in 'from each according to his ability, to each according to his needs'. However, I feel that far too many are no longer interested in the first part of that maxim, whilst perfectly happy to go along with the second.