With the changes to the tax law that came in for the tax year ended 5th April 2017, significant changes were required to the tax return. Unfortunately not all of these changes could be implemented in HMRC’s tax calculation software, meaning certain taxpayers would not have their tax calculated correctly. Those returns including the affected changes, referred to as exclusions, should have been rejected by online filing systems. As a result, a paper return should have been submitted instead. Despite this, approximately 30,000 returns affected by these exclusions have been filed.

From 19th November 2018, HMRC began reviewing the affected returns to see if the calculations were incorrect. Those in which they found an error should have attracted an amended tax calculation (SA302) from HMRC showing the figures they consider to be correct.

Any affected taxpayers should have received this notice by now. Due to the potentially complex nature of the exclusions it will be advisable for most to engage the services of a professional to review this. Regardless of whether you take advice or not, anyone receiving one of these amended tax calculations should act as soon as possible.

If you believe the amendment to be incorrect, then you need to lodge notice of appeal with HMRC within 30 days of the date of the notice.  Otherwise, you should pay any additional tax due as soon as possible. This tax will not be subject to interest from the original due date for that tax year (31st January 2018) but will become subject to interest from 28 days of the date of the notice.


We hope you have enjoyed reading this article. The future of our volunteer led, non-profit publication would be far more secure with the aid of a small donation. It only takes a minute and we would be very grateful.