Corporation Tax for large businesses was 28% in 2010, 21% for small companies. The current rate is 20% with the aim to reduce this to 18%.
So this is a reduction of 10 percentage points or a reduction of nearly 36%. For small companies the fall is 3 percentage points or just over 14%.
The new extra tax on dividends effectively gives everyone a tax free dividend allowance of £5K, beyond this the rates are increased by 7.5%, which is a 30% increase for people who were paying the extra tax at 25%.
So yes it is an increase in tax but it is probably more a case of giving you a tax cut and increase. It would have been better to have reformed the company taxes/dividend taxes at the same time.