Common HMRC Queries During Tax Return Season: A Complete UK Guide 

During tax season, taxpayers across the UK rush to gather their records and submit their Self Assessment tax returns. It can bring a lot of questions, particularly if you are self-employed or are filing a Self Assessment tax return for the first time. In these situations, you need useful guidance to help you with your common HMRC queries during tax return season.

This comprehensive guide answers some of the questions you are most likely to have, using the latest guidance published by HM Revenue & Customs (HMRC). After reading this guide, you will get the details right, which can help you avoid unnecessary penalties and unexpected tax bills.

What Is a Self-Assessment Tax Return and Why Does It Matter?

A self-assessment tax return is a system in the UK used by HMRC to collect Income Tax and Capital Gains Tax (CGT). This tax is collected from individuals whose tax is not automatically deducted from wages via Pay As You Earn (PAYE).

Remember the Self Assessment tax return deadline because failing to report untaxed income accurately and on time leads to heavy HMRC penalties.

What Are the Common HMRC Queries During Tax Return Season?

Taxpayers can have many HMRC Self Assessment tax return queries when submitting their tax returns. Some of the common HMRC queries during tax return season are:

Who Needs to Complete a Self Assessment Tax Return?

First of all, you must know that not everyone needs to submit a Self Assessment tax return. You must send one if certain circumstances apply to you. For instance, you need to submit a return if you were:

Self-employed as a sole trader and earned more than £1,000 in gross trading income, before deductions.

• A partner in a business partnership
• Had to pay CGT when you sold or disposed of an asset that increased in value
• Had to pay the High Income Child Benefit Charge and do not pay it through PAYE

Moreover, certain off-payroll workers who are repaying a student or postgraduate loan may also need to submit a return.

What is the Self Assessment Tax Return Deadline?

One of the most common HMRC queries during tax return season concerns HMRC Self Assessment deadlines.

For the 2026 to 2027 tax year, which runs from 6 April 2026 to 5 April 2027, HMRC’s current deadlines are:

• Paper tax return: HMRC must receive it by 31 October 2027.
• Online tax return: HMRC must receive it by 31 January 2028.
• Tax payment: Tax owed must be paid by 31 January 2028.
• Second payment on account to HMRC: Where applicable, this is due by 31 July 2028.

It is better to submit your return early rather than waiting until the deadline. Filing early can help you understand how much you owe. It can also give you more time to budget for the payment.

How to Register for Self Assessment?

Another common HMRC query taxpayers ask during tax return season is about HMRC Self Assessment registration.

The simple answer is, you must tell HMRC by 5 October following the tax year you had untaxed income. Create a Government Gateway Account on the official HMRC website and submit your personal and employment details. Then, wait for your 10-digit Unique Taxpayer Reference (UTR) letter in the post.

Do I Actually Need to File a Return This Year?

One of the absolute most common HMRC queries during tax return season is whether a taxpayer’s income and circumstances trigger a filing requirement. It is important to check if you need to file a tax return. You do not need to guess your status.

You can use the official, interactive HMRC check if you need a tax return tool available on the official HMRC website.

What Happens if I Make a Mistake on My Tax Return?

Mistakes can happen, especially when you are completing a return with multiple sources of income. If you make a mistake, you may be able to amend your Self Assessment tax return after submitting it.

Generally, you can amend a return within 12 months of the Self Assessment deadline. For example, a return for the 2025 to 2026 tax year would usually need to be amended by 31 January 2028.

If you filed your tax return online, you must wait 3 days (72 hours) after filing before updating it online. Furthermore, if more than 12 months have passed, different rules apply, and you may need to contact HMRC or consider whether another form of relief applies.

Which Expenses Can I Claim on My Tax Return?

When it comes to the common HMRC queries during tax return season, the question regarding allowable expenses in Self Assessment cannot be ignored. People often ask what expenses they can claim on their Self Assessment tax return.

If you are self-employed, certain business costs can be deducted that are associated with running your business, such as:

• Travel costs
• Certain professional fees
• Advertising and marketing costs
• Office and equipment costs
• Business insurance and financial charges

What Happens if I Cannot Afford My Self Assessment Tax Bill?

You can make payments towards your Self Assessment bill before the deadline. If you cannot pay your tax bill, you may also be able to arrange a payment plan with HMRC, depending on your circumstances. However, you should still file your tax return on time to avoid late-filing fines.

You can make weekly or monthly payments towards a future Self Assessment bill through a Budget Payment Plan if you meet the relevant conditions.

Keep in mind that failing to pay on time can result in interest and, where applicable, penalties or further recovery action.

Final Thoughts on Common HMRC Queries During Tax Return Season

Understanding the most common questions before submitting a tax return can make Self Assessment less stressful for taxpayers. The key is to check whether you need to file, keep accurate records, understand allowable expenses, and differentiate between your tax bill and any payments on account.

It is better to check HMRC’s official guidance for the latest rules that apply to your situation, because your tax circumstances can vary.

If you are not sure you can manage your self-assessment tax return or HMRC deadlines, hire a qualified accountant. At AccountingFirms, we help you find the best accountant who can handle your tax returns effortlessly. You can search, compare, and select an accountant within just minutes.

Disclaimer: The information provided on AccountingFirms.co.uk is for informational purposes only and should not be considered as financial advice. Always consult with a professional accountant to ensure compliance with UK laws and regulations.