The UK Tax Return for the 2025–2026 financial year is a key responsibility for millions of taxpayers. Whether you are self-employed, a contractor, a landlord or a company director, filing your tax return correctly and on time is essential.
This guide explains everything you need to know about the 2025–2026 tax return, including who must file, deadlines, allowable expenses, common mistakes and why working with a trusted tax accountant in Milton Keynes can save you money and protect you from HMRC penalties.
What Is a Tax Return in the UK?
A tax return, officially known as a Self Assessment Tax Return, is how individuals and businesses report income, expenses and tax owed to HMRC.
The tax return covers income earned between 6 April 2025 and 5 April 2026. Once submitted, HMRC calculates whether you owe tax or are due a refund.
Who Needs to File a Tax Return for 2025–2026?
You may need to submit a tax return if you:
- Are self-employed or a sole trader
- Work as a contractor or CIS subcontractor
- Are a company director
- Earn rental income from property
- Receive dividends or investment income
- Have overseas income
- Earn income not taxed through PAYE
Many people in Milton Keynes are required to file a tax return without realising it, which often leads to penalties.
Tax Return Deadlines for the 2025–2026 Tax Year
Meeting deadlines is critical.
- Tax year: 6 April 2025 to 5 April 2026
- Online tax return deadline: 31 January 2027
- Tax payment deadline: 31 January 2027
Even a one-day delay can result in an automatic penalty.
Allowable Expenses That Can Reduce Your Tax Bill
Claiming allowable expenses correctly can significantly reduce how much tax you pay.
- Business travel and mileage
- Office and equipment costs
- Phone and internet
- Professional fees such as accountants
- Marketing and advertising
- Home office expenses
Expenses must be wholly and exclusively for business purposes.
Common Tax Return Mistakes
- Missing the 31 January deadline
- Declaring incorrect income figures
- Forgetting allowable expenses
- Poor record keeping
- Trying to file without professional advice
These mistakes often result in higher tax bills or penalties.
New HMRC Penalties and Stricter Enforcement
While the main responsibility remains filing your tax return correctly, HMRC has introduced stricter enforcement measures that affect late or non-compliant taxpayers.
Recent changes include a penalty points system for late submissions and faster application of fines for repeated non-compliance. This means taxpayers who regularly miss deadlines may face escalating penalties rather than one-off fines.
In addition, interest charges on unpaid tax have increased, making delays more expensive than ever. These changes highlight why filing on time and accurately for the 2025–2026 tax year is crucial.
Why Professional Tax Support Matters
HMRC now cross-checks data from employers, banks, CIS records and property income. Errors are detected faster, and penalties are issued automatically.
Working with a professional accountant reduces the risk of mistakes, ensures all allowable expenses are claimed and provides peace of mind.
Tax Accountant in Milton Keynes
Leader Accountancy supports individuals, contractors and businesses across Milton Keynes with expert tax return services.
- Self Assessment Tax Returns
- CIS tax returns
- Tax planning and advice
- HMRC compliance support
- Clear and personalised service
Need Help With Your Tax Return 2025–2026?
Avoid penalties and overpaying tax. Speak to a trusted tax accountant in Milton Keynes today. Book Your Tax Consultation
Frequently Asked Questions – Tax Return 2025–2026
What is the deadline for the 2025–2026 tax return?
The deadline to submit your online tax return is 31 January 2027.
What happens if I miss the deadline?
You may receive an automatic penalty and additional charges if the delay continues.
Do I need to file a tax return if I am self-employed?
Yes. Self-employed individuals must submit a Self Assessment Tax Return.
Can an accountant help reduce penalties?
Yes. Professional support ensures correct and timely filing, reducing the risk of penalties.