The personal tax allowance for 2018/19 is£11,850.
Not everyone has the benefit of the full personal allowance. There is a reduction in the personal allowance for those with ‘adjusted net income’ over £100,000, which is £1 for every £2 of income above £100,000. So for 2017/18 there was no personal allowance where adjusted net income exceeded £123,000. For 2018/19 there is no personal allowance available where adjusted net income exceeds £123,700.