If you’re an individual moving to the UK—or someone with UK income but no previous experience of the UK tax system—Self Assessment may be a new concept. While you may be familiar with tax returns in your home country, the UK approach is quite different.
In the UK, the responsibility is on you as the taxpayer to:
HMRC does not usually calculate or confirm your final tax bill for you. If you file late or pay late, you will be penalised—even if you don’t owe much (or any) tax.
We’re here to make this process easier. We specialise in helping overseas individuals navigate the UK Self Assessment system with clear, accurate, and timely tax filings.
You’ll need to register for Self Assessment if any of the following apply to your UK situation:
If you’re not sure whether you need to register, we can help you check your position and register you if required.
Once registered, you’ll be responsible for the following:
Each year, you’ll need to file a Self Assessment tax return (SA100) reporting your UK income, deductions, and any reliefs you’re claiming. If relevant, you may also need supplementary pages (such as the SA103 for sole traders or SA105 for landlords).
We will complete and submit this electronically on your behalf using HMRC-recognised software. Paper returns are not relevant for our clients and are typically not accepted if you need to file special pages like the SA109 (for non-residents).
Tax returns cover income for the UK tax year, which runs from 6 April to 5 April. Deadlines are:
| Action | Deadline |
|---|---|
| Register for Self Assessment | 5 October after the tax year ends |
| File online tax return | 31 January after the tax year ends |
| Pay tax due (balancing payment + 1st payment on account) | 31 January |
| Pay 2nd payment on account (if applicable) | 31 July |
Most individuals pay in three stages:
We’ll send you reminders and clear payment instructions.
Once your tax return is submitted:
HMRC has up to 12 months from the date you file your return to open an enquiry. During this time, they may ask questions or request documents if anything appears unusual.
They use data-matching systems and receive information directly from:
If your return does not match the information HMRC holds, it may trigger an enquiry.
Once the enquiry window has closed, your return becomes final—unless HMRC later uncovers evidence of careless or deliberate errors.
If you’re new to the UK tax system, we’ll handle the process from start to finish:
Self Assessment is the UK system for individuals to report income and pay tax. You must register with HMRC, calculate your own tax, and file a return by the annual deadline. It’s your responsibility—not HMRC’s—to ensure everything is correct and on time.
If you have UK-source income (such as rent or trading income), then yes, you may need to register and file a tax return, even if you are not a UK resident.
No. In the UK, you are responsible for working out your tax and reporting it. HMRC only reviews your return if they open an enquiry.
You must register online with HMRC by 5 October following the end of the tax year in which you first became liable. We can register you and handle all communication with HMRC on your behalf.
While technically allowed, it is not suitable for our clients. Many of the forms you need (especially if you are non-resident or claiming treaty relief) cannot be filed via HMRC’s basic system or by paper. We file all returns online using approved software.
You’ll be fined GBP 100 automatically. Additional penalties apply if your return is more than 3 months late, and interest and further charges apply to late tax payments.
Yes, if you made a mistake or used provisional figures, you can amend your return up to 12 months after the deadline.
These are advance payments towards your next year’s tax bill, based on this year’s tax. They’re usually due on 31 January and 31 July.
You’re not legally required to have one, but we strongly recommend it—especially if you’re unfamiliar with the UK system. We make sure everything is filed accurately and on time and help you avoid double taxation.
We offer a free initial consultation, so you can understand what’s needed with no obligation.
Get in touch with us today to make your UK tax compliance easy and stress-free.
Managing Director
Senior Manager
Head of Direct Taxes
