Good news for UK taxpayers registering for Self Assessment for the first time

HM Revenue and Customs (HMRC) has launched an upgraded online registration service that issues new Self Assessment customers their Unique Taxpayer Reference within 72 hours instead of up to 15 days by post.

HMRC announced the changes as it urged anyone with income to declare for the 2025 to 2026 tax year to register now. More than 640,000 people registered for Self Assessment in the 12 months to 31 March 2026.

Anyone filing a Self Assessment return for the first time for 2025 to 2026 must register by 5 October 2026 or risk a penalty. The deadline to submit the return and pay any tax owed is 31 January 2027, but nobody can start a return until they hold a Unique Taxpayer Reference.

“Anyone new to Self Assessment may not realise they need to register before they can submit their tax return. Registering is quicker and easier than ever,” said Myrtle Lloyd, Chief Customer Officer at HMRC.

“And if you register now, you’ll get your Unique Taxpayer Reference so you can start completing your return with plenty of time before the 31 January deadline,” she added.

New customers sign up through their Personal Tax Account, which they can create using Government Gateway or GOV.UK One Login details. HMRC said the streamlined process includes:

• Forms pre-populated with the customer’s existing information
• Signposting to online support during registration
• Save and return functions with no loss of data
• A confirmation email or text once registration is complete

The new service covers individual customers with a Personal Tax Account only. Agents registering on behalf of clients must continue to use the existing CWF1 and SA1 forms.

HMRC’s free online checking tool on GOV.UK tells people whether they need to file a return at all. The full list of reasons someone may need to file includes those who:

• Are newly self-employed and have earned gross income over £1,000
• Earned below £1,000 but want to pay Class 2 National Insurance voluntarily to protect their State Pension entitlement
• Are a new partner in a business partnership
• Have received any untaxed income over £2,500

The £1,000 trading allowance means anyone earning under that amount in a tax year does not need to declare it or pay tax on it.

Anyone who no longer needs to complete a tax return must tell HMRC as soon as possible, or the department will still expect a return and issue a penalty for non-submission. Existing customers who skipped the 2024 to 2025 return will need to reactivate their account before filing for 2025 to 2026.

HMRC also confirmed that around 300,000 Self Assessment customers will now see their or their partner’s Child Benefit payments pre-populated on their online return.

This targets people liable for the High Income Child Benefit Charge, some of whom can now pay it monthly through their tax code via the PAYE digital service instead of filing a return at all.

Pensioners in Self Assessment who received the Winter Fuel Payment, or the Pension Age Winter Heating Payment in Scotland, will see it pre-populated on their 2025 to 2026 online return where possible and should add it manually if it is missing.

Anyone with total income over £35,000 repays it through their Self Assessment bill, with paper filers adding it to returns due by 31 October 2026.

The deadline to opt out of the Winter Fuel Payment is 23:59 on 20 September 2026, and midday on 19 October 2026 for the Scottish payment. Customers signed up to Making Tax Digital for Income Tax still need to submit their Self Assessment return and pay by 31 January 2027.

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