Self Assessment Tax Returns London — Expert Accountants for Sole Traders & Individuals

Filing a self assessment tax return can feel overwhelming, especially if your financial situation has become more complex — multiple income sources, rental income, dividends, capital gains, or business profits. At ProKeeper, our experienced self assessment accountants in London take care of the entire process for you, ensuring your return is accurate, on time, and structured to minimise your tax liability legally.

Do You Need to File a Self Assessment Tax Return?

You must file a self assessment tax return if, in the last tax year, any of the following applied:

• You were self-employed as a sole trader and earned more than £1,000
• You were a partner in a business partnership
• Your total taxable income was over £100,000
• You received income from renting out property
• You received dividends from company shares
• You received foreign income
• You had capital gains (e.g. from selling a property or investments)
• You received the High Income Child Benefit charge (income over £60,000)
• You received income not taxed at source, including savings interest or untaxed pension income

If you’re unsure whether you need to file, contact our team — we’ll advise you quickly and without obligation.

Our Self Assessment Tax Return Service

ProKeeper handles every aspect of your self assessment from start to finish:

• HMRC registration — if you’ve never filed before, we register you for self assessment with HMRC as your authorised agent
• Tax return preparation — we gather all your income, expenses, and relief information and prepare an accurate, complete return
• Allowable expense review — we identify all allowable deductions you’re entitled to claim, reducing your tax bill legally
• Capital gains calculation — accurate CGT calculations for disposals of property, shares, and other assets
• Rental income returns — we handle income from UK property, including furnished holiday lettings and HMOs
• Foreign income reporting — we ensure overseas income and assets are reported correctly, including double taxation treaty claims
• HMRC submission — we file your return with HMRC electronically before the deadline
• Tax liability calculation — we tell you exactly how much you owe and when, well in advance of payment deadlines
• Payments on Account — we explain and manage your payments on account so there are no nasty surprises in January

Key Self Assessment Deadlines

• 5 April — End of the tax year
• 5 October — Deadline to register for self assessment (if you’re filing for the first time)
• 31 October — Deadline for paper tax returns
• 31 January — Deadline for online tax returns AND payment of any tax owed, plus first payment on account for the following year
• 31 July — Second payment on account due

Missing the 31 January deadline results in an automatic £100 penalty, with further penalties and interest accruing the longer the delay. ProKeeper ensures your return is filed well ahead of the deadline — we aim to have all client returns completed by December each year.

Allowable Expenses for Sole Traders

One of the most valuable parts of our service is ensuring you claim every allowable expense. Sole traders and self-employed individuals can typically deduct:

• Office costs (stationery, phone, broadband)
• Travel and vehicle costs (mileage allowance or actual costs)
• Clothing (uniforms and protective gear)
• Staff costs if you employ people
• Marketing and advertising
• Professional fees (accountants, solicitors)
• Training costs relevant to your business
• Use of home as office (if applicable)

Our team reviews your income and expenditure carefully to ensure you don’t pay a penny more tax than you legally need to.

Self Assessment Pricing

Our self assessment tax return service starts from £150 for a straightforward return (e.g. sole trader with employment income). More complex returns involving multiple income sources, property, or capital gains are priced accordingly. Contact us for a fixed-fee quote — we’ll always give you a clear price upfront, with no surprises.

Frequently Asked Questions — Self Assessment Tax Returns

What’s the penalty for filing my tax return late?

There’s an automatic £100 penalty if your return is up to 3 months late. After 3 months, you’re charged £10 per day (up to 90 days). After 6 months, there’s a further penalty of the higher of £300 or 5% of the tax due. Interest also accrues on any unpaid tax. Working with ProKeeper eliminates this risk entirely.

I’ve never filed a self assessment before — where do I start?

Hand it to us. We’ll register you with HMRC as your authorised agent, gather the information we need from you, and handle everything from that point onwards. You don’t need to know anything about the self assessment process — that’s what we’re here for.

What if I owe tax from previous years?

If you have overdue or unfiled returns, we can help. We’ll prepare and submit any outstanding returns, liaise with HMRC to minimise penalties, and set up a payment plan if needed. It’s always better to regularise your position than to continue ignoring it — HMRC’s investigation powers are extensive.

Can I file my own self assessment return?

Yes, but many people make mistakes — missing deductions, incorrect figures, or misunderstanding complex rules. These errors can lead to an overpayment of tax or, worse, an HMRC investigation. A professional self assessment accountant ensures accuracy and saves you time, stress, and often money. See our bookkeeping service if you’d also like help keeping your records in order throughout the year.

Let Us Handle Your Self Assessment Return

Tax return season doesn’t have to be stressful. Hand your self assessment to ProKeeper’s London accountants and we’ll make sure it’s filed accurately, on time, and structured to keep your tax bill as low as legally possible.

Book a free consultation with our self assessment team today