Who Can File My Self Assessment Tax Return?

A tax return can feel like the last job standing between you and a proper evening off. If you are asking, who can file my self assessment tax return?, the short answer is: you can file it yourself, or you can appoint somebody to act for you. But handing over the paperwork does not hand over your legal responsibility. HMRC still expects the return to be complete, accurate and submitted on time.

For a straightforward return, doing it yourself may be perfectly sensible. For a subcontractor sorting CIS deductions, a landlord with several properties, a cab driver with day-to-day running costs, or a limited company director juggling salary, dividends and expenses, professional help can prevent costly omissions and take a sizeable job off your plate.

Who can file your self assessment tax return?

You may submit your own return through HMRC’s online service, or on paper where this is appropriate. You can also appoint an authorised tax agent, usually an accountant, to prepare and submit it for you.

A spouse, partner, friend or family member can help gather figures and complete the form. However, if they are going to deal with HMRC on your behalf, they need the right authority in place. Do not assume that being married, running the business together or having access to your records automatically lets someone discuss your tax affairs with HMRC.

An accountant is often the most practical choice because they can do more than enter numbers in boxes. They can review the records behind those numbers, ask about missed expenses, calculate the tax position and submit the return as your authorised agent. They can also deal with routine HMRC correspondence relating to the return once authority has been set up.

What appointing an agent actually means

Your agent can usually prepare and file your self assessment return online using commercial software. HMRC authorisation allows them to access relevant tax information and communicate with HMRC for agreed services. The precise process depends on the authority being used, so it is worth setting this up early rather than trying to do it on the January deadline day.

You should still read the return before it is submitted. A good accountant will explain the figures in plain English, flag up anything that needs your confirmation and give you a copy of the final return and tax calculation. You are the person making the declaration that the information is correct to the best of your knowledge.

When filing it yourself makes sense

Self-filing can work well if your affairs are genuinely simple. Perhaps you have one source of self-employed income, clear records, no complex claims and the time to work through the return carefully. HMRC’s system guides you through the main sections, and many people manage without an agent.

The trade-off is that HMRC’s form is designed to collect information, not to advise you on the best tax treatment for your circumstances. It will not necessarily tell a sole trader which legitimate costs have been overlooked, whether capital allowances may apply, or how to deal with an expense that is partly business and partly personal.

If you choose this route, start early. This gives you time to find missing invoices, check bank transactions and understand an unexpected tax bill. It also reduces the chance of filing in a rush and guessing at figures.

When an accountant is likely to save you trouble

Professional support is particularly worthwhile where the records are more involved or the tax rules are not obvious. That does not mean you need to be running a large company. A one-person business can have complicated tax issues.

For example, a CIS subcontractor may have tax deducted at source throughout the year. Those deductions need recording correctly so that the final calculation reflects tax already paid. A small mistake can delay a refund or leave you paying more than necessary.

Landlords need to separate rental income and allowable property costs, consider the treatment of mortgage interest and account for repairs correctly. Limited company directors need to distinguish personal self assessment from the company’s accounts and corporation tax return. Taking money from the company is not always the same as receiving a salary, and the way it has been recorded matters.

You may also benefit from help if you have sold a property or investments, received substantial dividend income, have income from abroad, or need to claim expenses that require careful judgement. These are all situations where an accountant can provide clarity before a figure is sent to HMRC.

At Short And Sons Accountants, the work is not just about getting a return filed. It is about understanding how you earn, whether that is on the road, on site, through rental property or via your own company, then making sure the return reflects the position properly.

Can a bookkeeper or payroll provider file it?

Possibly, but check exactly what is included. A bookkeeper may keep your records in good order but may not offer tax return preparation or tax advice. A payroll provider handles wages and PAYE reporting, which is separate from preparing your personal self assessment return.

Likewise, software can help organise records and generate reports, but software does not take responsibility for deciding whether a cost is allowable or whether all your income has been included. It is a useful tool, not a substitute for checking the tax position.

Before appointing anyone, ask whether they will prepare the return, submit it to HMRC, explain the calculation, deal with queries and advise on payments on account. A clear scope avoids the unpleasant surprise of discovering that filing, amendments or HMRC correspondence cost extra.

What you still need to provide

Even the best accountant cannot file an accurate return without timely information from you. Keep business and personal spending as separate as possible, retain invoices and receipts, and provide records in a usable format. A bank statement alone may show that money was spent, but not always what it was for or whether it had a business purpose.

For self-employed people, this commonly includes sales records, expenses, bank statements, mileage details where relevant, CIS statements and details of any other income. Landlords should provide rental statements, agent fees, repair invoices and finance costs. Directors may need P60s, dividend vouchers, pension information and confirmation of benefits or other personal income.

Be open about anything unusual. Cash income, a new side business, cryptocurrency disposals, a property sale or income earned abroad can all affect the return. It is far easier to deal with these properly before filing than to correct the position after HMRC asks questions.

The deadline is not the only date that matters

For most people filing online, the deadline for a tax return covering the tax year ending 5 April is 31 January following the end of that tax year. Any balancing payment is generally due on the same date. Penalties can apply if the return is late, even where there is little or no tax to pay.

There may also be payments on account towards the following year if your bill meets HMRC’s criteria. This catches many newly self-employed people out because the first significant payment can include tax due for the year just ended plus an advance payment for the next one.

An agent can file your return, but they cannot make missing records appear or remove a late-filing penalty caused by waiting too long to start. Getting your information together well before January gives you more options, more time to check the figures and a clearer view of what needs to be paid.

Choosing the right person to file for you

The cheapest option is not always the best value if it results in poor records, missed reliefs or an unsupported claim. Look for someone who understands the type of work you do, explains matters without jargon and is clear about what they need from you.

You should also be wary of anyone promising an unusually large refund before reviewing your documents. A refund may be due, especially where CIS tax has been deducted, but it should be based on proper records and a return you understand. If HMRC later challenges the claim, it is still your tax position at stake.

The right support should leave you with less admin, more confidence in the figures and a realistic plan for paying what is due. Start the conversation before the deadline pressure builds - a calm review of your records is usually far more useful than a frantic January submission.