ON WEDNESDAY April 22nd, Britain's finance minister announced that from April 2010 a new 50% rate of income tax will be levied on high earners. This will be among the highest top rate of income tax in the world's richest countries, with only Sweden taking more. But taxation is rarely simple. At $218,055, the income level at which Britain's new rate kicks in is considerably higher than in Sweden or Belgium. Switzerland and America may seem softer on their high earners, but local income taxes could bump up the top rate in those countries to over 40%.