Can I reduce Self Assessment Payments on Account?

You can reduce Payments on Account for Self Assessment.

Payments on Account are based on income declared in the previous tax year. If you believe that you income will be reduced in the current tax year and therefore the tax due will be less than the previous year, HMRC allows you to reduce payments on account once you have informed them.

This can either be done as part of the Self Assessment you submit for the previous tax year or through your Government Gateway. However if you do not inform HMRC that you are applying to reduce payments on account they will assume you are underpaying tax and apply penalties.

If having informed HMRC that you are reducing payments on account, it turns out that you have under estimated tax due, HMRC will not apply penalties but will apply interest on the underpaid amount.