HMRC has launched an improved online Self-Assessment registration service, designed to make it quicker and easier for individuals to register and start completing their tax return.
The change is particularly important for anyone who needs to submit a Self-Assessment tax return for the 2025/26 tax year for the first time.
If this applies to you, you should normally tell HMRC by 5 October 2026.
In this guide, Accounting People explains what has changed, who may need to register, how quickly you can receive your Unique Taxpayer Reference (UTR), and the key Self-Assessment deadlines you need to know.
What Has Changed With Self-Assessment Registration?
HMRC introduced its improved Self-Assessment registration service in September 2026.
The service is available to individual taxpayers through their Personal Tax Account and is intended to make the registration process more straightforward.
Improvements to the service include:
- information being pre-populated where HMRC already holds it
- clearer access to online support during registration
- the ability to save an application and return to it later without losing information
- email or text confirmation once registration is complete
The aim is to reduce some of the administration involved in registering for Self-Assessment and make it easier for taxpayers to complete the process online.
If you are unfamiliar with your Personal Tax Account, you can also read our Personal Tax Account guide.
When Do You Need to Register for Self-Assessment?
If you need to complete a Self-Assessment tax return for the 2025/26 tax year, you should tell HMRC by 5 October 2026 if you:
- have not submitted a Self-Assessment tax return before; or
- were previously registered but did not need to submit a tax return for 2024/25 and now need to submit one for 2025/26.
You tell HMRC by registering for Self-Assessment.
The 5 October date should not be confused with the deadline for actually submitting your tax return.
Key Self-Assessment deadlines for 2025/26
| Requirement | Deadline |
| Tell HMRC you need to complete Self-Assessment | 5 October 2026 |
| Paper tax return | 31 October 2026 |
| Online tax return | 31 January 2027 |
| Pay tax due | 31 January 2027 |
For online returns, the normal filing deadline is 11:59pm on 31 January 2027.
What Happens If You Register After 5 October 2026?
If you miss the 5 October registration date, you should register as soon as possible rather than waiting until January.
Where someone registers after 5 October 2026, HMRC will provide a different filing deadline. This will normally be three months from the date of HMRC’s letter or email.
However, this does not extend the normal deadline for paying the tax you owe. Any tax due must still generally be paid by 11:59pm on 31 January 2027.
Registering late does not automatically mean that a fixed penalty will be charged. However, if you register after 5 October and do not pay all the tax due by 31 January, HMRC says you may receive a failure-to-notify penalty.
If you think you have missed the registration deadline, Accounting People can help you understand what you need to do next.
How Quickly Will You Receive Your UTR?
Once you register for Self-Assessment, HMRC will issue you with a Unique Taxpayer Reference, usually referred to as a UTR.
A UTR is used by HMRC to identify you within the Self-Assessment system.
One of the main improvements to the new registration service is the time it can take to receive this number.
HMRC says people using the new service will receive their UTR in their online account within 72 hours, rather than potentially waiting up to 15 days for it to arrive through the post.
This should make it easier for newly registered taxpayers to get started with their tax return.
However, it is still a good idea to register as early as possible. Receiving your UTR is only part of the process, and you may need time to gather your financial records and prepare your return accurately.
Who May Need to Register for Self-Assessment?
There are several reasons why you might need to complete a Self-Assessment tax return.
You became self-employed
If you are a sole trader and your gross trading income was more than £1,000 during the tax year, you will normally need to complete a Self-Assessment tax return.
It is important to understand that this refers to gross income before deducting expenses or tax reliefs, rather than your final profit.
You became a partner in a business partnership
If you become a partner in a business partnership, you will normally need to complete your own Self-Assessment return.
The partnership itself also has separate tax reporting responsibilities.
You received untaxed income
You may need to complete a tax return if you receive income that has not already been taxed.
Examples can include:
- income from renting out property or land
- tips and commission
- savings interest
- dividends
- foreign income
- certain other taxable income
The rules depend on both the type and amount of income, so you should not assume that receiving untaxed income automatically means you either do or do not need Self-Assessment.
If you are uncertain, Accounting People can help you check whether a tax return is required based on your circumstances.
What About the £1,000 Trading Allowance?
The trading allowance can provide relief of up to £1,000 of qualifying gross trading income in a tax year.
If your annual gross trading income is £1,000 or less, you will often not need to report that income to HMRC solely because of the trade.
However, there are exceptions.
For example, you may still need or choose to complete a return if you want to:
- pay voluntary National Insurance contributions where eligible
- claim certain trading losses
- claim expenses instead of using the trading allowance
- report another source of income that creates a Self-Assessment requirement
The £1,000 figure relates to gross trading income rather than profit after expenses.
Can You Register to Pay Voluntary National Insurance?
There are circumstances where someone with relatively low self-employed income may still choose to register or complete Self-Assessment.
For example, eligible individuals may want to pay voluntary National Insurance contributions to help protect entitlement to the State Pension or certain benefits.
Whether this is worthwhile will depend on your National Insurance record and individual circumstances, so it is sensible to check your position before making voluntary contributions.
What If You Were Previously Registered for Self-Assessment?
If you already have a UTR, do not automatically assume that there is nothing else you need to do.
HMRC says taxpayers who were already registered for Self-Assessment but did not submit a tax return for 2024/25 may need to reactivate their account if they now need to submit a return for 2025/26.
This means that having an old UTR does not necessarily mean your Self-Assessment account is currently active for the return you need to file.
If you previously stopped filing Self-Assessment returns and your circumstances have now changed, check your position as soon as possible.
What If You No Longer Need to Complete a Tax Return?
If HMRC is expecting a tax return from you, but you believe you no longer need to complete one, you should not simply ignore it.
You should tell HMRC that your circumstances have changed and that you believe a return is no longer required.
HMRC has advised taxpayers who no longer need to complete a tax return to notify them as soon as possible. Until HMRC confirms otherwise, you should continue to meet your existing Self-Assessment obligations.
Your circumstances might have changed because you:
- stopped being self-employed
- stopped receiving a particular source of untaxed income
- left a business partnership
- no longer meet another condition that previously required a return
Whether you can stop filing will depend on your individual circumstances and HMRC’s position.
Can Accounting People Register You for Self-Assessment?
The new Personal Tax Account registration service is aimed at individuals registering themselves.
Different HMRC procedures apply where registration is being dealt with by an accountant or tax agent.
HMRC has confirmed that agents should continue to use the existing agent registration processes where appropriate rather than the new individual Personal Tax Account process.
If you are unsure which registration method applies, Accounting People can help you determine the correct route and assist with your wider Self-Assessment obligations.
Changes to High Income Child Benefit Charge Information
HMRC has also introduced changes intended to make dealing with the High-Income Child Benefit Charge (HICBC) easier for some taxpayers.
Around 300,000 Self-Assessment taxpayers are expected to have their own or their partner’s Child Benefit payment information pre-populated on their online Self-Assessment return.
This is intended to make it easier for taxpayers affected by the charge to complete their return accurately.
Some people who would otherwise complete a Self-Assessment return solely to pay the High-Income Child Benefit Charge may also be able to deal with the charge through PAYE, provided they meet HMRC’s eligibility requirements.
If you need to complete a tax return for another reason, different requirements may apply.
What Does Making Tax Digital Mean for Self-Assessment?
Making Tax Digital for Income Tax (MTD) began applying to the first mandatory group from 6 April 2026.
For the 2026/27 tax year, taxpayers generally need to use MTD for Income Tax if they are within its scope and their qualifying income for 2024/25 was more than £50,000.
The threshold is being reduced in stages:
- qualifying income over £50,000 – from 6 April 2026
- qualifying income over £30,000 – from 6 April 2027
- qualifying income over £20,000 – from 6 April 2028
Qualifying income broadly means gross income from self-employment and property before expenses and tax.
Being within MTD does not remove the need to complete the relevant year-end tax process.
HMRC has confirmed that taxpayers using Making Tax Digital for Income Tax must still submit their tax return and pay the tax due for 2025/26 by 31 January 2027.
If you are a sole trader or landlord and are unsure whether MTD now applies to you, speak to Accounting People before your next reporting deadline.
Winter Fuel Payment and the 2025/26 Tax Return
There are also changes affecting taxpayers who received the Winter Fuel Payment.
Where possible, HMRC will pre-populate Winter Fuel Payment information on the 2025/26 online Self-Assessment return for taxpayers who received the payment.
You should still check the information carefully and add it manually if it is missing.
If your total income is over £35,000, HMRC will generally recover the Winter Fuel Payment through the tax system.
For people who complete Self-Assessment, the amount is normally recovered through their Self-Assessment tax bill.
The online opt-out deadline for the Winter Fuel Payment is 11:59pm on 20 September 2026. Separate arrangements apply in Scotland for the Pension Age Winter Heating Payment.
As these rules are time-sensitive, check out the latest government guidance if you are reading this article after the dates above.
What Do You Need Before Completing Your Self-Assessment?
Registering for Self Assessment is only the first step.
Depending on your circumstances, you may need information covering:
- self-employed income and business expenses
- employment income
- pension income
- property income and allowable expenses
- savings and investment income
- dividends
- capital gains
- pension contributions
- charitable donations
- Child Benefit
- student loan information
- other taxable income
Keeping complete and accurate records can make preparing your return considerably easier and reduce the risk of mistakes.
Need Help With Your 2025/26 Self-Assessment?
The new HMRC registration service should make it easier to get started, but determining what needs to go on your tax return can still be complicated.
At Accounting People, we help individuals, sole traders, landlords, company directors and other taxpayers understand their Self-Assessment obligations and prepare their returns correctly.
We can help you with:
- checking whether you need to register
- Self-Assessment registration
- preparing your tax return
- identifying allowable expenses and relevant tax reliefs
- calculating your tax liability
- understanding Payments on Account
- dealing with HMRC correspondence
- Making Tax Digital requirements
- keeping on top of important tax deadlines
If you need help with your 2025/26 Self-Assessment tax return, speak to Accounting People for clear, professional support based on your circumstances.
Find out more about our Self-Assessment services or contact our team.
Important information
This article is intended for general information only and does not constitute personalised tax, financial or legal advice. Tax rules, thresholds and HMRC guidance can change, and how the rules apply will depend on your individual circumstances. If you are unsure about your tax position, seek professional advice before taking action.
