This is important to ensure a fair tax system. Everyone should be treated equally.
In the 2010 – 2011 tax year, people who earn over £100,000 a year get their Personal Allowance reduced by £1 for every £2 of income above this amount, eventually losing it altogether – this is totally unfair and should be reversed. A personal allowance should be just that and everyone should get one. High earners pay more than enough tax anyway.