CGT Return Amendment and Penalties UK – 30-Day Return Rules (Part 3 of 3)

Introduction to CGT Return Amendment and Penalties UK

If you've submitted a Capital Gains Tax (CGT) return for a UK property disposal and later discover an error, you may be able to amend it. In this final part of our CGT blog series, we explore how to correct your CGT return and the penalties that may apply for late or incorrect submissions. This guidance is essential for staying compliant with the CGT return amendment and penalties UK framework.

When Can You Amend a CGT Return?

You can amend a CGT return if you discover that the reported gain or the amount of tax paid is incorrect. You can only amend the return if the error relates to events on or before the completion date of the disposal. You can now change your own return online in your Capital Gains Tax on UK property account. You cannot change returns for 2023/24 or earlier online, and you cannot change a return online once the Self Assessment return for that year has been filed. Agents and others acting for you use a form instead.

Importantly, once you file the Self Assessment tax return for that year, you can no longer amend the CGT return. From that point, you must make any changes directly on the Self Assessment return only.

➡️ Relevant legislation: FA 2019, Sch 2, Part 2, para 19(3)

If additional tax is due, it's best to pay it as soon as the error is discovered.

Handling Overpayments and Underpayments

If additional tax is due, it's best to pay it as soon as the error is discovered. Delays could result in interest charges.

In cases where tax was overpaid, the overpaid amount can usually be relieved during the same tax year. For instance, if there is another disposal later in the year, the overpaid tax can be offset against the gain on the second disposal.

➡️ Relevant legislation: FA 2019, Sch 2, Part 1, para 8

Interest on Late Payments

Interest is charged on any unpaid CGT from the day after the 60-day deadline (60 days from completion) to the actual date HMRC receives the payment.

➡️ See: FA 2019, Sch 2, Part 3, para 31 ; FA 2009, s 101(3), (4)

Penalties for CGT Return Amendment and Payment Delays

Late Filing Penalties (FA 2009, Sch 55)

The harmonised penalty regime in FA 2009, Sch 55 applies.

• £100 fixed penalty if filed late
• £10 daily penalties after 3 months late
• 5% of tax due (or £300 if higher) after 6 and 12 months

These penalties are typically issued retrospectively, as HMRC often becomes aware of the disposal only after the return is filed.

Late Payment Penalties (FA 2009, Sch 56)

The harmonised penalty regime in FA 2009, Sch 56 applies.

• 5% of unpaid tax after:
  • 30 days from 31 January following the tax year
  • 6 months after 31 January
  • 12 months after 31 January

Final Thoughts on CGT Return Amendment and Penalties UK

Understanding how to amend a CGT return and avoid penalties is crucial for landlords, property sellers, and tax advisors alike. This concludes our 3-part guide on the 60-day CGT reporting rule UK.

⬅️ Missed something? Start with Part 1 of our CGT series, or review Part 2 on CGT payment.