Every year, thousands of people in Kent receive a letter from HMRC asking them to file a Self Assessment tax return, and every year, thousands more who should be filing one simply do not. If you are wondering whether you need to complete a tax return, you are not alone. The rules are not always obvious, and getting it wrong in either direction can be costly.
This guide explains exactly who needs to file, what the deadlines are, and what happens if you ignore it.
Quick Answer
You need to file a Self Assessment tax return if your income is not fully taxed at source through PAYE, or if HMRC has sent you a notice to file. Common triggers include self-employment income, rental income, income over £100,000, and untaxed savings or investment income above certain thresholds.
Who Has to File a Self Assessment Return?
HMRC requires you to file a Self Assessment return if any of the following applied in the tax year:
- You were self-employed as a sole trader and earned more than £1,000
- You received rental income from a property
- Your total taxable income was over £100,000
- You received untaxed income from savings, investments or dividends
- You made capital gains above the annual exempt amount (£3,000 from 2024/25)
- You or your partner received Child Benefit and either of you earned over £60,000
- You received income from abroad
- You were a company director receiving income not taxed through PAYE
- HMRC sent you a notice requiring you to file
If none of these apply, you almost certainly do not need to file. If you are unsure, it is worth checking rather than assuming either way.
What If You Only Have PAYE Income?
Most employees in the UK pay all their tax through Pay As You Earn (PAYE), which means their employer deducts the correct amount before they are paid. If this is your only income and your tax code is correct, you do not need to file a return.
However, even employed people sometimes need to file. If you have multiple employers, receive taxable benefits like a company car, or have side income from freelance work or property, PAYE alone will not cover everything. HMRC may also issue a notice to file if they believe your affairs are more complex than a standard employment.
The Self-Employment Threshold
If you are self-employed, you must register with HMRC and file a return if your gross trading income exceeds £1,000 in a tax year. This is the trading allowance, and it applies even if you made a loss overall.
Many people who do casual work, sell items online, or take on freelance projects alongside their main job do not realise this threshold applies to them. The £1,000 is based on total income before expenses, not profit.
Rental Income and Landlords
If you receive rental income from a property in the UK, you must file a Self Assessment return unless your total property income is under £1,000 (the property allowance). Most landlords will comfortably exceed this, even with a single property.
Your rental profit (income minus allowable expenses) is added to your other income and taxed accordingly. Section 24 has also changed the way mortgage interest is treated, which makes accurate tax returns more important than ever for buy-to-let landlords.
High Earners and the £100,000 Threshold
If your total income exceeds £100,000, you are required to file a return regardless of whether you are employed, self-employed, or both. This is because HMRC withdraws the personal allowance above this level at a rate of £1 for every £2 earned, and your tax code alone cannot handle this accurately.
It also gives you the opportunity to reclaim pension contribution relief and other deductions that do not come through PAYE automatically.
The Child Benefit High Income Charge
Since April 2024, the High Income Child Benefit Charge kicks in when either partner earns more than £60,000. If you or your partner received Child Benefit payments and either of you earns above this threshold, you must file a Self Assessment return to pay back some or all of that benefit.
What Are the Deadlines?
If you need to file a Self Assessment return for the 2024/25 tax year:
- Register with HMRC by 5 October 2025 (if you have not filed before)
- Paper return deadline: 31 October 2025
- Online return deadline: 31 January 2026
- Pay any tax owed: 31 January 2026
Missing these deadlines triggers automatic penalties, even if you end up owing no tax.
What Happens If You Should Have Filed But Did Not?
If HMRC discovers that you should have been filing Self Assessment returns and have not, they can go back up to 20 years in cases of deliberate non-disclosure, or 6 years for careless errors. Penalties include a percentage of the unpaid tax, daily charges, and interest.
Voluntary disclosure is always treated more favourably than being caught. If you think you may have missed returns, getting a tax specialist involved early is the sensible move.
FAQs
I only earned a small amount from self-employment. Do I still need to file? Yes, if your gross self-employment income exceeded £1,000 in the tax year. Even if you made very little profit after expenses, the filing obligation still applies. You can claim the £1,000 trading allowance instead of actual expenses if your income was low.
HMRC sent me a notice to file but I do not think I need to. What should I do? You need to either file the return or contact HMRC to have the notice withdrawn. Ignoring a notice to file will result in penalties even if you owe no tax. If you believe the notice was issued in error, a tax specialist can help you challenge it.
I was employed all year but had some savings interest. Do I need to file? Probably not. Basic rate taxpayers have a £1,000 Personal Savings Allowance, and higher rate taxpayers have £500. If your savings interest was below these thresholds, you are covered. Above the threshold, you may owe tax, but HMRC can often collect small amounts through your tax code rather than requiring a full return.
I have not filed for several years. What should I do? Contact a tax specialist as soon as possible. The longer you leave it, the larger the penalty exposure. In most cases, getting everything filed voluntarily and correctly will result in far lower penalties than waiting for HMRC to come looking.
Can I file my own return or do I need an accountant? You can file your own return using HMRC’s online service. However, if your affairs involve rental income, self-employment expenses, capital gains, or multiple income sources, using a qualified tax specialist will almost always save you more than it costs by ensuring every allowance and deduction is correctly claimed.
Get Your Self Assessment Sorted
Our principal tax adviser is an ACCA and ATT qualified tax specialist and HMRC Registered Agent with over 25 years of personal tax experience. Kent Tax Specialists handles Self Assessment returns for sole traders, landlords, employees and high earners across Gravesend, Dartford, Maidstone, Medway, Sevenoaks, Tonbridge, Tunbridge Wells, Canterbury and the wider Kent area. Get in touch today for honest advice and a fixed-fee quote.
Also see: Self Assessment in Gravesend | Self Assessment in Dartford | Self Assessment in Maidstone
