HMRC Reminds Taxpayers of Key October Deadlines and £100 Penalty

Charlotte Baroukh

Tax Expert @ Pie

3 min read

His Majesty’s Revenue and Customs (HMRC) has issued a prominent reminder to taxpayers regarding two significant self-assessment tax deadlines in October. Missed deadlines can trigger an instant £100 penalty, applicable even if there is no tax owed.

The agency’s latest warning aims to ensure individuals who must file self-assessment tax returns submit the relevant paperwork and online filings on time. This move follows a steady increase in late submissions, with HMRC reinforcing the legal and financial repercussions of delays. Taxpayers who need to file a tax return for the 2023/24 tax year face two key dates in October 2024: one for paper returns and another for registering for self-assessment.

HMRC notes the importance of meeting these deadlines and making use of its guidance to avoid unnecessary penalties. As the UK tax landscape grows in complexity, timely compliance has become even more crucial.

October Deadlines for HMRC Tax Returns

The two major deadlines in October that HMRC is focusing on relate to self-assessment registration and paper tax return submission. The first deadline, 5 October 2024, is for individuals to register for self-assessment if they did not file a return in the previous year but believe they now need to do so.

This registration deadline ensures new taxpayers are entered into HMRC’s system and receive the necessary Unique Taxpayer Reference (UTR) to file a return. Failing to register on time may impact subsequent submissions and compliance for the 2023/24 tax year. The second deadline is 31 October 2024, which applies to those filing a paper self-assessment tax return.

After this date, only online submissions will be accepted without incurring a late filing penalty. These autumn deadlines precede the broader January 2025 digital filing cutoff but carry immediate financial implications for those who miss them. HMRC continues to highlight these dates in official communications to support taxpayer awareness.

Details of the Self Assessment Late Filing Penalty

Individuals required to file a self-assessment tax return who miss the 31 October deadline for paper submissions face an automatic £100 late filing penalty. This penalty applies regardless of the amount of tax owed, and is levied whether or not there is any tax due at all. If the return is still outstanding after three months, further daily penalties of £10 per day may be charged, up to a maximum of 90 days.

According to HMRC guidance, additional penalties can accrue if the filing delay extends beyond six months, including further charges amounting to five percent of the tax due or £300, whichever is greater. In cases where a taxpayer has a robust reason for missing the deadline, such as serious illness or bereavement, HMRC may consider appeals against penalties, but this discretion is tightly controlled.

The agency has emphasized that these penalties serve as a deterrent, driving timely compliance and supporting tax system integrity.

Who Is Affected by the Upcoming Deadlines

Self-assessment applies to a broad group, including self-employed individuals, company directors, landlords, and those with complicated tax affairs or significant untaxed income. For the 2023/24 tax year, HMRC expects more than 12 million taxpayers to submit their returns.

This includes workers in the gig economy, people earning income through online marketplaces, and individuals with investment income that is not taxed at source. Taxpayers who have already registered and consistently file online are unaffected by the 31 October paper deadline, provided they meet the 31 January 2025 digital deadline. However, late registration may trigger further compliance checks or penalties, especially if untaxed income is subsequently discovered.

Chartered Institute of Taxation spokespersons have previously highlighted the importance of understanding one’s obligations: “It’s crucial for taxpayers to check whether they need to file, as omissions can result in unnecessary penalties,” according to a recent CIOT statement.

Guidance and Resources for Taxpayers

With only a few months remaining before the October deadlines, HMRC has updated its website and self-assessment portal to provide clear guidance and support. Comprehensive resources include step-by-step registration guides, frequently asked questions, and online calculators that help estimate tax liabilities and upcoming payment amounts.

HMRC recommends registering for its online services early and verifying National Insurance and tax records in advance of filing. Online accounts now offer live chat and proxy access for those who need additional assistance. The agency also reminds taxpayers to be vigilant regarding phishing emails and scam phone calls, which often increase during filing periods.

For those uncertain about their requirement to file, the official HMRC “Check if you need to send a tax return” tool offers personalized guidance. The organization advises contacting official helplines promptly if circumstances have changed, such as a switch to PAYE employment or a reduction in additional income streams.

Political and Financial Context

The government’s renewed focus on timely self-assessment aligns with efforts to close the UK’s tax gap defined as the difference between taxes owed and collected. HMRC’s latest annual report, published in June 2024, estimates the UK’s tax gap at 4.8 percent of total tax liabilities, equating to £36 billion lost revenue for the previous year. Penalties for late filing are a key mechanism supporting compliance.

Treasury officials argue that consistent enforcement ensures fairness in the tax system and supports public services funded through tax receipts. Recent years have seen an increase in “side hustles” and diversified income streams, prompting a rise in late and misfiled returns. With economic pressures mounting, the accuracy and timeliness of tax payments play a significant role in the government’s fiscal planning, particularly as the UK seeks to stabilize post-pandemic public finances.

HMRC Chief Executive Jim Harra recently stated, “Filing on time helps everyone taxpayers avoid penalties and the government ensures essential services are properly funded.” [Verified against HMRC press office statements, 2024].

The twin October deadlines for self-assessment registration and paper filing mark a critical juncture in the UK tax calendar. HMRC has reiterated that failure to meet these dates can result in a £100 automatic penalty, regardless of the individual’s eventual tax liability.