There is a gradual withdrawal of the personal allowance if your taxable income exceeds £100,000.  This is via a reduction of £1 of allowance for every £2 of excess taxable income.

For 2013/14

Taxable income	Marginal rate
£100,000 to £118,880	60%
£118,881 to £149,999	40%
£150,000 +	45%

For 2014/15

Taxable income	Marginal rate
£100,000 to £120,000	60%
£120,001 to £149,999	40%
£150,000 +	45%

If your income is likely to be approaching £100,000 for the current tax year then you should consider keeping income levels just below that level taking action to reduce the number of years in which you exceed that threshold. For example, this might be achieved through careful timing of dividend income.