Last Month to File Your 2023–24 Tax Return: What You Need to Do Now

This guidance is for Self Assessment taxpayers who are approaching the end of the filing window for the 2023–24 tax return and want to check whether they are already late.

As the final month approaches, confusion often arises between filing deadlines and payment deadlines. Missing the filing deadline can trigger automatic penalties, even if the tax itself is paid on time. This page explains how to tell whether you are already late and what that means, with practical self assessment advice in London for those unsure where they stand.

Final Steps to Take Before the 31 January Self-Assessment Deadline

The 31 January 2025 deadline for self-assessment tax returns is fast approaching. Avoid penalties and last-minute stress by filing your return and paying any tax due promptly. Don’t forget, first-time filers need to register for HMRC’s online service without delay.

You should also be aware that payment of any tax due should also be made by this date. This includes the remaining self-assessment balance for the 2023-24 tax year, as well as the first payment on account for the 2024-25 tax year.

A recent press release by HMRC has highlighted the fact that 4,409 taxpayers took the time to file their tax return online on Christmas Day with a further 11,932 taxpayers completing their tax returns on Boxing Day. In total, 40,072 self-assessment returns were filed between 24 and 26 December, figures often cited by a tax consultant in London when explaining how filing behaviour is changing. The total number of submissions for the period was significantly more than in the previous year.

What Happens If You Are Late Filing the 2023–24 Tax Return

If a 2023–24 Self Assessment tax return is filed after the deadline, HMRC will normally issue an automatic £100 late filing penalty. This applies regardless of whether any tax is owed or whether the tax is paid on time.

If the return remains outstanding, daily penalties of £10 per day may apply once the return is three months late, up to a maximum of £900. Further penalties can follow if the return is still not filed after six months and twelve months.

In Practice – Why Many People Are Late Without Realising

In practice, we often see taxpayers assume there is a short grace period after the deadline or confuse the filing deadline with the payment deadline. Unfortunately, HMRC applies late filing penalties automatically once the deadline passes, even if payment is made on time.

For practical guidance, experienced accountants in Fulham Broadway support taxpayers across nearby areas such as Walham Green and Sands End when Self Assessment returns have been filed late and penalties are a concern. At CIGMA Accounting, our team can help you confirm whether you are already classed as late and advise on the steps that may help limit further charges from HMRC.

Check Whether You Are Already Late Filing Your 2023–24 Return

If you are unsure whether the filing deadline has passed for your 2023–24 tax return, clarifying this now can help prevent further penalties. A short review can confirm where you stand and what action is still possible.