Along with having just one rate, the personal allowance would be raised, and many unfair taxes like Inheritance tax and the tax on share dividends would be scrapped altogether.
But doesn't this sound like a windfall for the rich and a recipe for a public spending disaster?
Experience suggests otherwise. When tax rates are cut, as they were in the 1980's, the rich actually pay more, as they don't bother with tax avoidance schemes. It's those on lower incomes who gain most, by the higher tax-free allowance. As for there being less money for schools and hospitals, yes, there would be a shortfall for a year or two which would have to be covered by extra borrowing. However, cutting taxes has been proven to make the economy grow, so the extra money required would soon be made up. One of the main appeals of flat rate taxation is its simplicity, so why haven't the other parties considered it? Perhaps because if any future chancellor tries to bring in allowances to favour minority groups whose votes they are chasing, or to introduce stealth taxes, they will be easier to spot!
Sadly it seems only UKIP believes in open government these days.
(With Thanks to Gerard Batten UKIP MEP)