What would be the problem with abolishing VAT entirely, and relying on increased income tax to replace it?
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As for the suggestion that the only reason anyone would want a more responsiblt job is because of getting much higher payment, that just isn't how a lot of people work. Having more say over what goes on, and knowing you can make a difference is rewarding in itself. In any unpaid activity there is no problem in finding people who are eager to take a leading role.   

Determining which of a number of candidates is best equipped for a leading role is nothing to do with who wants the most money.    There is no reason to assume that by reducing the money you would be particularly likely to eliminate the people who are best equipped to do the job.