Anyone who failed to submit their Self Assessment tax return by the January 31 deadline is being urged to file their return as soon as possible to avoid any further penalties. HM Revenue and Customs (HMRC) has previously said that more than 12 million people were expected to file a self-assessment tax return for the 2024/25 year. People who submit their return late face an immediate £100 fine.
If the delay reaches three months, daily penalties of £10 per day can be applied, rising to a maximum of £900. After six months, HMRC can add a further charge equal to 5% of the tax due or £300, whichever is higher, with another penalty at the same level imposed after 12 months.
Those who fail to pay their bill by the deadline will also face separate penalties. HMRC can add charges of 5% of any unpaid tax after 30 days, six months and 12 months, as well as interest on the outstanding balance, meaning the amount owed can increase rapidly.
HMRC wrote on X (formerly Twitter) on February 1: “Anyone who missed the deadline should file their return as soon as possible to avoid any further penalties. Search ‘Self Assessment’ on http://GOV.UK to find out more.”
Tax returns can be filed online through GOV.UK. First-time filers must register for Self Assessment before submitting a return, while those who have previously used the service may need to reactivate their account. Returns do not need to be completed in one sitting and can be saved and finished later.
Anyone who believes they have a reasonable excuse for missing the deadline can appeal a penalty, although any fines issued must usually be paid within 30 days of the notice being sent.
You must send a tax return if, in the last tax year (6 April to 5 April), any of the following applied:
- you were self-employed as a ‘sole trader’ and earned more than £1,000 (before taking off anything you can claim tax relief on)
- you were a partner in a business partnership
- you had to pay Capital Gains Tax when you sold or ‘disposed of’ something that increased in value
- you had to pay the High Income Child Benefit Charge and do not pay it through PAYE
The government has said that you may also need to send a tax return if you have any untaxed income, such as:
- money from renting out a property
- tips and commission
- income from savings, investments and dividends
- foreign income
If you are unsure whether you need to submit a tax return, you can check online on the government website. You must notify HMRC by 5 October if you need to complete a tax return for the previous tax year and either have not sent a tax return before or have previously registered but did not need to file one for 2023 to 2024. This is done by registering for Self Assessment.
Even if you are not required to file, you may choose to complete a tax return to claim certain Income Tax reliefs, prove your self-employment status, for example, to claim Tax-Free Childcare or Maternity Allowance or to make voluntary National Insurance contributions.