Effective income tax rates in the UK (1)

Table updated April 2010.

In the context of nothing in particular, here's a summary of effective tax rates (including Employee's and Employer's National Insurance and Tax Credit withdrawal) on the three main groups of working-age taxpayers (by income level) for the main types of income*:
Conclusion: a flat rate of tax would particularly benefit lower earners, especially if combined with a much higher tax-free personal allowance; £9,125 seems a good place to start - see point (b) here. Provided the flat rate were 41% or less, it wouldn't hurt basic rate employees (which is the most important and largest group by source of income).

* I didn't bother with interest income - as RPI inflation and typical bank interest rates are both about 5%, the tax/tax credit withdrawal is in most cases > 100% of the real income. Rental income assumes that the 10% wear and tear allowance is claimed and no other expenses. Dividend income assumes that the paying company has already paid 30% corporation tax.