From The World Is Flat: But America is a laggard in the tax-reform revolution:
In Britain, die-hard opponents of the flat tax, such as Chancellor of the Exchequer Gordon Brown, were caught censoring portions of an internal Treasury paper on the subject that was obtained under the recently effective Freedom of Information Act. The unexpurgated version, leaked to the Daily Telegraph, found that a flat tax would likely make Britain more attractive to foreign investors, eliminate economic distortions and create a ‘mini-economic boom.’ The paper noted that under flat-tax systems in other European countries the rich end up paying a larger share of total tax revenues. In flat-tax countries, taxpayers in the highest brackets move from consumption or tax-sheltered investments to more productive, taxable investments. Many higher earners work harder or take additional risks, rewarded by higher after-tax returns.