Self Assessment Tax Returns
If you are self-employed, a company director, a landlord, or earn income above the HMRC threshold, you must file a Self Assessment tax return every year. It is one of the most common — and most easily mishandled — tax obligations for UK individuals. Our London accountants prepare and file your Self Assessment accurately, claim every relief you are entitled to, and make sure you never face a late-filing penalty.
Who needs to file a Self Assessment
You must file a Self Assessment tax return if you are self-employed as a sole trader earning above the trading allowance, a company director, a partner in a business partnership, a landlord receiving rental income, or an individual with income above £100,000 or from savings, investments or foreign sources above certain thresholds.
Even if you are employed and pay tax through PAYE, you may still need to file if you have additional untaxed income, receive child benefit above the threshold, or have capital gains to report. We help you confirm whether you need to file — and take care of it if you do.
How we prepare your return
You provide your income details, P60s, and records of any expenses, dividends or rental income. We calculate your overall tax position, apply every eligible relief and allowance, and prepare your SA100 tax return for your review. Once you approve it, we submit it directly to HMRC through our agent portal.
Because we look at your full financial picture — not just a form — we often identify reliefs and deductions that reduce your bill. We also tell you clearly how much tax you owe and when, so there are no surprises on the payment deadline.
Deadlines and penalties
The key Self Assessment deadline is 31 January each year for both online filing and payment of any tax owed. Missing it triggers an automatic £100 penalty, with further charges the longer the return remains outstanding. We track your deadline and file early so you never incur one.
Frequently Asked Questions
When is the Self Assessment deadline?
Online returns and any tax owed are due by 31 January each year. We recommend filing well before Christmas to avoid the January rush.
What happens if I miss the deadline?
HMRC issues an automatic £100 penalty, with further charges the longer the return is outstanding, plus interest on unpaid tax. We file early so this never happens.
Can you claim expenses I did not know about?
Yes. We review your full circumstances and claim every legitimate expense and relief, which often reduces the tax you owe.
I am a company director — do I still need to file?
Almost always. Company directors usually need to file a personal Self Assessment to report salary, dividends and any other income. We handle both your company and personal returns.
How much does a Self Assessment cost?
Your fee is agreed on a free call before any work starts, based on the complexity of your affairs. There are no hidden charges.