The following is an update from HMRC included in its latest Agent Update 131.

It is a new tax year which means tax agents can now file their clients’ and their own 2024 to 2025 tax returns.

Here are the benefits of filing early and top tips for Self Assessment (SA) to ensure a stress-free and smooth tax season.

File your tax return early

The benefits of filing tax returns early are:

• reduced stress – you and your clients will be relieved when their tax return is out of the way, and means you can get on with other important things
• more time to correct errors – you will have time to correct any mistakes and ensure there are no consequences from getting it wrong
• improved client satisfaction – clients will realise the benefits of filing early and your support in organising them will help increase satisfaction with your services
• protection against identify fraud – we know fraudsters target taxpayers before the January deadline, so submitting client tax returns early helps safeguard them from opportunistic identity thieves
• better financial planning – filing early does not mean paying early, but customers will know what they must pay in advance so they can budget ahead of the payment deadline on 31 January 2026
• avoid penalties and interest – filing ahead of the deadline means your clients avoid the risk of late filing penalties
• give yourself time to prepare for Making Tax Digital (MTD) for Income Tax – MTD will become mandatory in phases starting from 6 April 2026, so getting tax returns out of the way gives you more time to prepare your clients and your business for the changes to come
• opportunity to reduce payments on account – filing early may provide an opportunity to accurately reduce the 31 July payment on account.

Tips for agents

Registering and reactivating Self-Assessment (SA)

It takes longer to process tax returns from customers who have not registered for SA prior to submitting their tax return or who did not reactivate their SA account.

People who are new to SA must register with HMRC so they can be set up on the system and receive a notice to file.

If your client has previously been in SA and did not file a tax return last year, make sure their account is reactivated before submitting their tax return. Returning SA customers do not need to register as new, as they already have a Unique Taxpayer Reference (UTR).

The quickest and easiest way to register and reactivate SA accounts is to do this online. Your client can do this in their online account.

If you need to do this for them, go online to find out how to register your client or reactivate a Self-Assessment account using one of the following forms:

• CWF1 for self-employed clients
• SA1 for clients who are not self-employed.

If you are not able to use the online service, you can contact us using webchat, by phone, or by using the print and post version of the forms.

Quickest way to get your clients Income and employment details

Use the Income Record Viewer to see your client’s:

• PAYE information for the current year plus the 4 previous tax years
• employment records, including time in employment and PAYE reference
• latest tax code for the current tax year including all allowances and deductions
• state and private pension information.

How to get tax returns and repayments right

To help speed up repayment requests you should:

• register or reactivate your client’s account for SA and wait until they receive their notice to file before submitting their tax return
• check the client’s details are correct and up to date, this includes their bank sort code, account number, UTR, National Insurance number, name and address
• leave 14 days after making a payment before you request a repayment otherwise it will be delayed
• make sure repayment requests for clients who were previously bankrupt are submitted using their post bankruptcy UTR
• notify HMRC of the capacitor if the client died before submitting their tax return and before requesting a repayment
• encourage your clients to receive their repayment electronically – Bacs is the quickest and most secure method.

Marriage allowance sequencing

Tax returns that include Marriage Allowance must be submitted in the correct sequence to avoid delays:

• the person transferring the allowance (transferor) should submit their tax return first if the person receiving the allowance (recipient) is also in SA
• the recipient should leave 72 hours after the transferor has submitted their tax return before submitting theirs.

Waiting for a reply

Use the Check when you can expect a reply from HMRC tool to check when you can expect a reply. Please wait until the due date has passed before you contact us.

Stopping Self-Assessment

If your client no longer needs to file a tax return you should contact HMRC as soon as possible. You can do this online, using webchat, by calling or writing to us. Your client can also do this online.

Read the Information on how to stop Self-Assessment which you can pass on to them to action.

If customers do not inform us that their circumstances have changed and they no longer need to be in SA, then we will continue to write to them, and they may get a penalty if they do not file on time.

Submitting a tax return as an amendment

It is good practice to submit your client’s tax return as an original, not as an amendment to avoid delays.

We receive a high number of tax returns submitted as an amendment using third party software, however, we have not received the original tax return.

This results in delays because these tax returns cannot be processed automatically. To make sure tax returns are processed quickly, submit the original tax return as normal and not as an amendment.

Repayments through PAYE

Check with your client if they received a repayment through PAYE and that it is included in their tax return before you submit a repayment claim through SA.

If a repayment has already been made through PAYE, HMRC will have to check the position manually to ensure that your client is not repaid more than they are due. This will delay your client’s claim.

Check if your client needs to complete a tax return

Use the check if you need to send a SA tax return tool to see if your client needs to complete a tax return.

Contacting HMRC

It is quicker and easier to use our online services for Agents. If you cannot use the online service and need to call or use our webchat service, have your client’s UTR and National Insurance number ready so we can deal with your call without delay.

When contacting the Agent Dedicated Line we will deal with a maximum of 5 customers per call. To maximise our service, we suggest you contact us with multiple clients rather than individually.

Updating your clients’ details

Delays often occur because client details such as name and address are not correct. Use our online services to amend your client details or ask them to update it in their HMRC online account.