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Moving to the UK from another country brings many adjustments. Understanding a new tax system is one of them — and HMRC does not offer leniency simply because you are unfamiliar with how it works. A recent First-tier Tribunal case confirmed this directly. A foreign national who missed a UK self-assessment deadline, arguing he did not understand the UK tax system, had his penalties upheld. The tribunal was clear: not knowing the rules is not a reasonable excuse. Our tax advisors at Tax Accountant regularly support foreign nationals, expats and international workers with UK tax compliance and this is one of the most common and costly misunderstandings we encounter.
What Happened in the Case
The taxpayer was a Canadian national who had previously lived and worked in Spain. On 24 January 2022, he registered for paperless communications with HMRC. HMRC issued a notice to file a self-assessment tax return for the year ending 5 April 2022 on 6 April 2022 via his personal tax account online. He logged into his account and read the notice. He did not submit the return by the deadline. HMRC imposed late filing penalties as standard.
The taxpayer appealed. He argued he was unfamiliar with the UK tax system and assumed UK requirements were similar to those in Spain. He also cited the complexity of the UK system following Covid-19 and Brexit, and said financial hardship from the collapse of his freelance tutoring business during the pandemic had prevented him from affording professional tax advice.
The First-tier Tribunal accepted that he faced genuine difficulties. It rejected his appeal regardless. The tribunal found that he had received the notice, read it and understood he needed to file. The obligation to comply with UK tax law applies equally to every taxpayer — regardless of nationality, background or previous experience with other tax systems. Ignorance of the law does not constitute a reasonable excuse.
What Is a Reasonable Excuse Under UK Tax Law?
The concept of reasonable excuse is central to penalty appeals. Where a taxpayer has a reasonable excuse for a failure to file or pay on time, HMRC must cancel the penalty. The bar for what qualifies is deliberately high. HMRC and the tribunals look for an unexpected or unforeseeable event that genuinely prevented compliance — not simply a reason why compliance was difficult or inconvenient.
Events that typically qualify as a reasonable excuse include a serious illness or medical emergency that prevented action, the unexpected death of a close relative shortly before the filing deadline, a confirmed technical failure on HMRC’s own systems at the time of filing, or a natural disaster causing severe disruption. The key word throughout is unexpected. Where a taxpayer could reasonably have anticipated a difficulty and taken steps to address it in advance, the excuse generally fails.
Events that do not qualify include not knowing about the filing requirement, being too busy to file, assuming someone else was handling it, lacking access to professional advice, financial difficulties making it hard to pay, or believing the UK rules would mirror those of another country. All of these have been tested before the tribunals repeatedly. None of them succeed as a reasonable excuse. HMRC’s guidance on reasonable excuses for late filing explains the standard HMRC applies.
Why Foreign Nationals Face a Particular Risk
Foreign nationals arriving in the UK often come from countries with very different tax systems. In some countries, employers handle all tax obligations automatically and individuals never need to file a personal return. In others, the self-assessment concept simply does not exist. It is entirely understandable that someone new to the UK might not immediately appreciate what is required of them.
However, understanding does not change the legal position. The moment a person becomes liable to file a UK self-assessment return — whether because of employment income, self-employment, rental income, foreign income or capital gains — they carry the same legal obligation as any UK-born taxpayer. HMRC will issue a notice to file. That notice creates a statutory obligation. Missing the deadline triggers penalties from day one, regardless of the taxpayer’s background or prior experience.
The case described above illustrates this precisely. The taxpayer read his notice to file. He knew the requirement existed. He simply did not act on it in time. His unfamiliarity with the broader system did not override the clear obligation the notice created.
Online Notices Are Legally Served
One specific point from this case is worth highlighting separately. The taxpayer had opted into paperless communications with HMRC. HMRC issued his notice to file through his personal tax account online. The tribunal confirmed this constituted valid service of the notice. The fact that the notice arrived digitally rather than by post made no difference to the legal obligation it created.
This matters for any taxpayer who uses HMRC’s online services. Opting into paperless communications means HMRC will send notices, reminders and correspondence through the personal tax account rather than by letter. If you do not monitor that account regularly, you risk missing notices that carry statutory deadlines. Our team advises all clients — particularly those new to the UK — to check their personal tax account regularly and set up email alerts for new correspondence through our personal tax services.
When Do Foreign Nationals Need to File a UK Tax Return?
Not every foreign national in the UK needs to file a self-assessment return. Whether you need to file depends on your specific circumstances. You are likely to need a UK self-assessment return if you are self-employed or a freelancer working in the UK, if you receive rental income from UK property, if you have foreign income that is taxable in the UK, if you are a company director, if your income exceeds £100,000, if you have capital gains to report, or if HMRC issues you with a notice to file regardless of your income sources.
Your UK tax residence status is the starting point for understanding your obligations. The UK Statutory Residence Test determines whether you are UK resident for tax purposes in any given tax year. Residence affects what income you pay UK tax on and what reliefs or treaty protections may apply. The rules are detailed and the outcome depends on specific day counts, ties to the UK and your pattern of visits. HMRC’s guidance on the Statutory Residence Test is the authoritative starting point, but applying it to individual circumstances often requires specialist advice. Our foreign income tax service covers the full range of issues that arise for internationally mobile individuals.
What Happens if You Miss a Filing Deadline
HMRC imposes penalties for late self-assessment returns automatically. A return filed one day late incurs a £100 fixed penalty. After three months, daily penalties of £10 per day apply for up to 90 days — a further £900. After six months, HMRC adds a penalty of 5% of the tax due or £300, whichever is higher. After twelve months, a further 5% or £300 applies, again whichever is higher. In cases involving deliberate withholding of information, the twelve-month penalty can reach 100% of the tax due.
These penalties accumulate regardless of whether any tax is actually owed. A nil tax return filed late still attracts the £100 fixed penalty. Many foreign nationals are surprised to discover this — they assume that if they owe no tax, there is nothing to worry about. That assumption is incorrect. The obligation to file and the obligation to pay tax are separate. Missing the filing deadline creates a penalty liability even where the tax liability itself is zero.
What to Do if You Have Already Missed a Deadline
If you have already missed a filing deadline, the priority is to file the outstanding return as soon as possible and pay any tax due. The longer the delay, the greater the penalty accumulation. Filing late but promptly limits the total penalty exposure and demonstrates to HMRC that you are taking the obligation seriously.
Where you believe you have a genuine reasonable excuse — for example a serious illness that genuinely prevented you from filing — you can appeal the penalties. The appeal must be made within 30 days of the penalty notice. Our tax appeals and disputes team handles penalty appeals regularly. We review the facts, assess whether a reasonable excuse argument is viable and manage the correspondence with HMRC on your behalf.
Where the position is more complex — for example where several years of returns are outstanding or where there is undisclosed foreign income — a voluntary disclosure is usually the more appropriate route. Making a disclosure before HMRC opens an enquiry attracts lower penalty rates than a prompted disclosure. Our HMRC disclosure facilities service covers this in full.
How Our Tax Advisors Can Help
The UK tax system is genuinely complex for anyone coming from a different tax environment. The rules around residence, foreign income, double taxation treaties and self-assessment obligations interact in ways that are not always obvious. Our team understands these challenges and works with foreign nationals, expats and internationally mobile individuals to get their UK tax position right from the outset.
We help clients identify whether they need to register for self-assessment, prepare and file outstanding returns, understand their residence position under the Statutory Residence Test, claim treaty relief where applicable and deal with HMRC where penalties or enquiries have arisen. We do this through our personal tax services, foreign income tax service and specialist tax services.
If you are a foreign national in the UK and are not sure whether you need to file a UK tax return — or if you already know you have missed deadlines — get in touch with our team as soon as possible. Acting early keeps your options open and limits the cost.