Leading article: Simplicity is a virtue

Now, though, taxation is returning to the political agenda in a big and radical way in a discussion that revolves around the so-called "flat tax". Partly this is because the - interim - new guard of the Conservative Party is looking favourably at the idea, and the Liberal Democrats are flirting with it, too. Partly, it is because the Treasury's miscalculations of tax credits have highlighted the complexity of the current system. And partly it is because the German centre-right is advocating a drastic simplification of the tax code in its election manifesto, and a flat-tax advocate could become Germany's next finance minister.

Above all, though, it is because what was once seen as a niche idea has been introduced in several of the former eastern bloc countries, including Russia, to impressive effect. Tax became less of a burden; it was easier to calculate and far more difficult to avoid. The revenue raised by the exchequers increased, as did consumer spending. Investors liked it, too - which matters in a world where there is global competition for investment. The success of the "new" European economies is the single reason why Germany could become the first of the advanced economies to try it.

And if Germany moves in that direction, other European countries - Britain included - could find it hard to resist. Indeed, the Treasury, it turned out last month, had already commissioned a study of the idea, but had scandalously blocked out the more favourable conclusions when it made its findings public.

The arguments commonly levelled against the flat tax are, first, that it could penalise lower income groups, who spend a greater proportion of their income on necessities and, second, that it would spell the end of redistributive taxation. Other studies, however, suggest that the better off would pay more, because loopholes would be closed. As for redistribution, much depends on the form and level of flat tax that would be applied.

The Chancellor may disagree, but simplicity and transparency are virtues, in taxation as in much else. A thorough review of our over-elaborate tax system is overdue, and a form of flat tax should at least be one of the options to be considered. It could be an idea whose time has come.