HMRC is urging the self employed, landlords and side hustlers to register for self assessment by 5 October deadline to get vital UTR number required for tax returns.

The deadline of Sunday 5 October affects self-employed workers, landlords, gig workers and people with side hustles, among others, who earned untaxed income during the 2024-25 tax year, ending 5 April 2025. They must register for self assessment by the deadline if they need to complete a tax return for the first time.

This is a piece of admin that is absolutely essential to ensure newbies to self assessment are issued with a Unique Taxpayer Reference (UTR), which is needed to complete their tax return. Many more people are likely to be impacted this year, especially with high interest rates meaning that people could fall foul of the tax on savings above various thresholds, the popularity of side hustles, crypto investors and ever growing number of users of online platforms to sell everything from holiday lettings to widgets.

But there is still hope if the deadline of 5 October is missed as that is ‘the deadline to notify chargeability’, and it is possible to sign up for self assessment at any time. However, there are penalties for late notification.

HMRC confirmed to Business & Accountancy Daily: ‘If a person needs to register for self assessment but has not done so by 5 October, they should still register for self assessment as soon as possible.

‘If they have a genuine reason for late notification, HMRC will take this into account when considering the penalty position. All penalties imposed by HMRC are appealable and where appropriate, may be cancelled.’

Missing the online registration deadline means the taxpayer will have to submit a paper tax return by 31 October 2025. If not, a late filing penalty will be issued by HMRC.

Anyone who is unsure if they need to submit a return can use HMRC’s online checking tool on gov.uk before registering.

Online self assessment taxpayers have until 31 January 2026 to complete their tax return and pay any tax owed for the 2024-25 tax year.

Anyone who no longer needs to file a self assessment tax return should let HMRC know as soon as possible. People will also need to tell HMRC if they have stopped being self-employed.

Myrtle Lloyd, chief customer officer at HMRC, said: ‘Thousands of people join self assessment each year and anyone new to self assessment for the 2024-25 tax year should register as soon as possible. Just search ‘register for Self Assessment’ on gov.uk to access a wide range of resources to help with registering and sign up today.’

Taxpayers paid through PAYE may also need to register for self assessment if they have additional income, such as from a buy to let or dividends, while directors and partners in a business partnership must use self assessment. This includes those who have received any untaxed income including pension income over £2,500.

It is mandatory for anyone self-employed as a sole trader who earned more than £1,000, before taking off anything that is liable for claim tax relief, to submit a self assessment tax return.    

Those who are self-employed and earn below £1,000 and want to pay Class 2 National Insurance contributions (NICs) voluntarily to protect their entitlement to state pension and certain benefits also need to sign up for self assessment. 

Side hustlers need to be very careful to comply with the rules, so for example sellers using Vintd, Facebook Marketplace and eBay, among others, who received income over £1,000 from trading or providing services online, fall under the self assessment umbrella. This includes online influencers and content creators, particularly those paid by companies to promote brands on their social media and websites, and receiving commercial sponsorship.

Cryptoasset gains also have to be notified to HMRC via self assessment, as does any interest on savings income received from banks totalling over £10,000.  

Watch out for the high income child benefit charge (HICBC) too, as if anyone claims child benefit and they or their partner had an income above £60,000, this kicks in. It is possible to opt out of course.

HMRC confirmed that pensioners do not need to include their 2025 winter fuel payment on their tax return for the 2024-25 tax year as payments received in autumn 2025 by those with income over £35,000 only will be recovered in the 2025-26 tax return, due by 31 January 2027.

Other reasons to have to do self assessment are for claiming tax relief for individual’s job expenses if this amounts to more than £2,500, capital gains tax (CGT) liabilities and declarations of foreign, offshore income. 

For the full list of who and what needs to be declared on self assessment, go to HMRC guidance, Self assessment tax returns.

Making Tax Digital for Income Tax coming soon

The income tax reporting system is changing radically in the next few years with the first tranche of sole traders and landlords with a qualifying income over £50,000 required to use Making Tax Digital (MTD) for Income Tax from 6 April 2026. This change will affect around 900,000 taxpayers from the new tax year, requiring quarterly reporting and a year-end update.

With just over six months to go before the new MTD rules kick in, HMRC stressed: ‘This marks a significant change and individuals with qualifying income will need to keep digital records, use MTD-compatible software and submit quarterly summaries of their income and expenses to HMRC.’

HMRC expects MTD to reduce errors in tax calculations and improve record-keeping, raising more income tax from this cohort.

Now there is an urgent call for taxpayers to sign up to trial MTD before it is introduced next year by registering for HMRC’s testing programme.

So far only 9,000 taxpayers and accountancy firms are signed up to the trial, so HMRC is ‘urging eligible customers to sign up to a testing programme on gov.uk to familiarise themselves with the new service and start preparing now’. Accountants and tax agents can register their clients via gov.uk.