HMRC issues ‘take action’ warning to Brits who missed tax deadline – but don’t call

The tax authority has issued a stark warning to anyone who has missed the Self Assessment tax deadline and is urging them to take action immediately

Brits who missed the Self Assessment tax deadline have been urged to take immediate action – but not to phone HMRC.

In a statement on X (formerly Twitter), HMRC said anyone who has fallen behind should submit their return online and pay any tax owed without delay. The tax authority warned: “Missed the Self Assessment deadline? No need to call. Take action immediately to file your return online and pay any tax owed. “.

The online service enables taxpayers to:

• Submit a Self Assessment if self-employed or if you receive other income, such as from renting out property.
• Check previous returns, view what you owe, and print tax calculations.
• Sign up for paperless notifications.

HMRC also reminded first-time filers that they must register for Self Assessment before using the service. Anyone with an existing account should ensure it is active to prevent delays. Certain taxpayers cannot use the online system, including partnerships, trusts, estates, non-resident people, and some other specialist cases. Commercial software or paper forms must be used instead.

To submit, you’ll need your Unique Taxpayer Reference (UTR) and to sign in to the service. HMRC may also ask for ID, such as a passport or driving licence, to verify your identity.

The warning comes as millions of Brits balance work, bills, and taxes – with penalties for late submission starting at £100, rising quickly the longer returns are delayed.

Late payment penalties.

• Initial penalty: A fixed penalty of £100 immediately after the deadline, even if there is no tax due.
• Three months late: Additional daily penalties of £10 per day, up to a maximum of £900.
• Six months late: An additional penalty of 5% of the tax you owe at this point.
• 12 months late: A further 5% penalty on the outstanding tax, plus potential extra penalties if HMRC deems the delay deliberate or careless.

HMRC also applies interest on unpaid tax from the due date until it’s paid. You can file your return online here.