Following a discussion with Matt Wardman, and using the data from James Smith, I produced one chart showing the marginal rate of Income Tax (ignoring the now almost entirely arbitrary split between income tax and NI). The second chart shows the percentage of total income paid as tax. Please feel free to use these in any way you see fit! (CC-BY-SA as usual - if you want the spreadsheet please email me).
Note the spike to a marginal rate of taxation of 61.5% between £100k and £113k. I have no sympathy with the rich, but this result seems ridiculous. Did they plan it? My bet is that it is yet another cock-up.