Personal Allowance Threshold (income >£100k)

The personal allowance £12,570 decreases by £1 for every £2 of adjusted net income* over £100,000 each tax year. This means the allowance is completely eroded if your income is £125,140 or above. 

There is no automated way that HMRC identify when taxpayers exceed the threshold during the tax year - tax is therefore underpaid and dealt with in arrears which can take up to two tax years.

If you know you will exceed the threshold, you can update your estimated income with HMRC online to ensure your personal allowance is reduced via your tax code accordingly. For more info on how to do this, see the attached.