Abbott and Brown
Self assessment

Self-Assessment tax return

Don’t miss deadlines and claim refunds and tax breaks with ease using our self-assessment tax return services.

When do I need to file a personal tax return?

Key scenarios in which an individual may need to file a self-assessment tax return with HMRC:

Self-employment: Trading profits exceeding £1,000 after the Trading Allowance.
Partnerships: Include partnership pages in your Self-Assessment if a partner in any business.
Property income: UK or overseas rental income, including Airbnb or holiday lets.
High untaxed income: Savings interest, dividends, or capital gains exceeding your personal allowances.
Company directors: If you receive dividends or any other untaxed income in addition to your director’s salary.
Other situations: Foreign income or gains, the high-income child benefit charge, or a specific HMRC notice to file.

When is the deadline to file a self-assessment tax return?

The deadline for filing a personal tax return in the UK is January 31 of the following year after the tax year has completed. For example, the deadline for the tax year ending 5 April 2026 is 31 January 2027.

Note: From 2026/27, Making Tax Digital for Income Tax requires quarterly updates, replacing the annual Self-Assessment return for eligible self-employed individuals and landlords only.

What happens if you miss the deadline?

Late submission of a UK Self Assessment tax return results in an immediate £100 fine, with penalties increasing the longer the return or payment is overdue.

Late Filing Penalties (after 31 January deadline)

1 day late: Automatic £100 fine.
3 months late: Additional £10 per day, up to a maximum of £900.
6 months late: Further penalty of 5% of the tax due or £300, whichever is higher.
12 months late: Another 5% of the tax due or £300, whichever is higher. In some cases, this can rise up to 100% of the tax due.

Late Payment Penalties (separate from filing)

30 days late: 5% of the unpaid tax.
6 months late: Further 5% of the unpaid tax.
12 months late: Additional 5% of the unpaid tax.
Self assessment

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How do we help you with your taxes?

Our step-by-step process will ensure you get the best tax advice to maximise your returns.

1
Personalised consultations

Our tax experts will review your income, investments, expenses, and upcoming payments that apply to the relevant tax year to fully understand your position and prepare your return accurately.

2
Action plan and recommendations

Our experts have the knowledge and experience to apply legitimate reliefs, allowances, and planning strategies to minimize tax liabilities, ensuring compliance with HMRC rules and that the correct amount of tax is paid.

3
Return filing with HMRC

Our team of accountants will submit your Self Assessment tax return to HMRC on your behalf, ensuring it is accurate and filed on time. We also monitor the process and promptly handle any queries pertaining to the submitted return.

Blog & insights

Expert advice, tax updates, and practical guides to help you make informed financial decisions.

Self Assessment deadlines, penalties and compliance for the tax year 2025/26 tax year
Tax compliance

Self Assessment deadlines, penalties and compliance for the tax year 2025/26 tax year

As the 2025/26 tax year progresses, it is important that taxpayers understand their obligations for reporting income and filing their Self Assessment tax returns with HMRC on time. Missing important...

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