I know this won't be relevant to most of the people who read this forum but the higher rate restriction on pension contributions will impact this tax year for alot of the people who earn over £150k. If you earn over £150k and make your pension contributions in one annual lump sum (and didn't do so by 22nd April) you'll only get higher rate tax relief on the first £20,000. The rest will only attract 20% relief. If you make regular payments to your pension (at least quarterly) you won't be affected and will get 40% relief on the whole amount no matter how large (so long as you are with A day limits).
This is a stealth tax which is likely to hit the self employed the hardest as they can predict their earnings with less accuracy and will tend to make annual payment contributions. It doesn't matter that you might be able to demonstrate that you've made the same level of contribution for a number of years - you will only get 20% relief on anything over £20k (and if you make regular contributions as well they will count towards the £20k limit).