Have you received an unexpected 2024/25 Self Assessment notice from HMRC? It may be linked to your savings interest

Why have I received a 2024/25 Self Assessment notice?

We understand that in mid-March 2026 HMRC issued notices to around 120,000 individuals asking them to file 2024/25 Self Assessment tax returns. 

Yes, you read that correctly: Even though 2024/25 was the tax year before last, these late notices to file have been issued to some people for the tax year ended 5 April 2025.

HMRC have said that these notices relate to bank and building society income. This follows improvements in the data HMRC receives from banks and building societies, which they say now allows them to more easily identify people whose interest income exceeds the Self Assessment criteria.

Where HMRC’s data showed that a person received more than £10,000 of interest in the 2024/25 tax year, but they did not complete a tax return, HMRC have now automatically registered them for Self Assessment and sent a notice to file. This is the first time HMRC have undertaken activity at this scale using this data. 

However, HMRC have said there were some cases where the person had also received a separate tax bill called a Simple Assessment for the same tax year – and this has caused some confusion for taxpayers. There has also been confusion caused by the deadline information shown in the tax return notices.

What does a notice to file mean?

If you have received a notice to file a Self Assessment tax return, it means HMRC are asking you to submit a tax return and pay any tax that may be due. 

The normal deadline for filing a Self Assessment tax return is 31 January following the end of the relevant tax year. However, if the notice to file has been issued after October 31 the deadline will be three months from the date shown on your notice. 

For this exercise, the 2024/25 notices were issued after 31 October 2025, but the deadlines shown in the letter heavily reference the 31 January 2026 filing deadline – which had already passed by the time the notices were sent to taxpayers! HMRC have acknowledged that this messaging was unclear.

The correct deadline for those who have recently received a notice to file a 2024/25 tax return is three months after the date shown on the notice. 

Received more than one notice or tax demand?

HMRC have said that around 14,000 customers have been additionally affected by an IT issue, which has resulted in these individuals receiving both a notice to file a Self Assessment tax return and a Simple Assessment tax calculation. Some individuals may have also received a P800 tax calculation. This should not normally happen.

HMRC is aware that for those receiving multiple communications, it has caused confusion and inconvenience and they are reviewing these cases. 

HMRC say they will be contacting affected individuals to confirm next steps, but we understand that the plan for those affected by the above IT issue will be as follows:

• Some individuals may have already paid the tax shown on the Simple Assessment, while also being told to complete a tax return for 2024/25. If this is the case for you, HMRC have confirmed that they will withdraw the notice to file a Self Assessment tax return, provided you do not have any other reason to file one for that tax year.
• However, if you have received a Simple Assessment or P800 tax calculation for the 2024/25 tax year, but have not yet paid the tax shown on it, HMRC say you will need to complete and submit a 2024/25 Self Assessment tax return instead. In these cases, HMRC say they will withdraw the Simple Assessment, and will write to you to confirm this is the case.

What if HMRC’s figures are wrong?

If you think the bank interest data HMRC holds is wrong, or if you have received a notice to file a 2024/25 tax return but do not think you had bank interest income exceeding £10,000, you should contact HMRC and keep any evidence that supports your position. Getting the interest figures right is important, as it may affect whether you need to complete a tax return and how much tax may be due.

Final words

Taking the time to check your savings interest will help you understand your position and ensure you take the right next steps.

If you meet the Self Assessment criteria for the 2025/26 tax year, you will still need to submit a Self Assessment tax return, even if your notice to file for 2024/25 has been withdrawn. For example, if you have more than £10,000 of bank interest, you will meet HMRC’s criteria to complete a Self Assessment return. 

You can use HMRC’s ‘Check if you need to send a Self Assessment tax return’ tool to work out if you meet the Self Assessment criteria, and find out how to register.