Is it worth filing a formal complaint with hmrc

When HMRC gets something wrong, it can feel like you’re shouting into the void. Whether they’ve miscalculated your tax bill, rejected a legitimate claim, or simply ignored your correspondence, the temptation to lodge a formal complaint might be strong. But is it worth the time and effort? The answer depends on several factors, and in this post, we’ll walk you through when a complaint makes sense and what you can realistically expect from the process.

Understanding HMRC’s Complaints Process

HMRC operates a two-stage complaints procedure, and it’s important to understand how it works before you invest your energy. First, you submit your complaint to the relevant HMRC office handling your case. They then have 30 calendar days to acknowledge it and up to four weeks to provide a substantive response. If you’re unhappy with their reply, you can escalate to Stage 2, where an independent caseworker will review the decision afresh. This second stage can take up to eight weeks.

The key question is whether your complaint falls within HMRC’s remit. They can only investigate complaints about their own service failures—such as delays in processing, incorrect advice, or failure to follow their own procedures. They cannot reopen a tax decision simply because you disagree with the law or believe the tax code is unfair. If your issue is fundamentally about the tax treatment itself rather than how HMRC has handled it, a complaint may not achieve what you’re hoping for.

When a Complaint Is Worthwhile

A formal complaint makes genuine sense in specific circumstances. If HMRC has delayed processing your Self Assessment return by several months beyond the deadline, causing you to miss payment deadlines or incur penalties, that’s a service failure worth documenting. Similarly, if you received conflicting advice from two different HMRC officers and acted on incorrect guidance, you have grounds for complaint.

Consider also the financial impact. If HMRC’s error has cost you significant money—perhaps they’ve wrongly disallowed a legitimate business expense or failed to process a valid claim for overpaid tax—then the complaint process might lead to compensation or a correction of your records. For example, if you overpaid tax by £500 or more due to HMRC’s mistake, pursuing a complaint could result in interest payments on top of the refund, which could make the effort worthwhile.

Another scenario is where HMRC has breached their own published guidance. HMRC issues detailed manuals and guidance on tax treatment. If they’ve applied a rule inconsistently with their own published position, that strengthens your complaint considerably. Keep copies of the relevant guidance—it demonstrates they’ve not followed their own standards.

When Complaints Often Struggle

Be realistic about outcomes. If your complaint centres on a genuine difference of opinion about how tax law applies, HMRC will almost certainly reject it at both stages. Tax law can be genuinely ambiguous, and HMRC’s interpretation, whilst not infallible, carries considerable weight. A complaint won’t override a legally sound decision, even if you believe it’s harsh.

Complaints also rarely succeed if you’ve simply missed a deadline or overlooked a requirement. HMRC isn’t required to chase you, and penalty notices are often upheld even when the taxpayer feels aggrieved. Similarly, if you’ve failed to keep adequate records—a common issue for sole traders and partnerships—HMRC’s estimation of your tax liability, whilst frustrating, typically stands.

Processing times are worth considering too. If HMRC is currently dealing with backlogs (as they have been following the pandemic), a complaint about delay may result in acknowledgment that they’re behind schedule, but little else. They’re not obligated to prioritise your case simply because you’ve complained.

Taking Action

Before lodging a formal complaint, exhaust other options. Request a detailed explanation from HMRC in writing. Sometimes a follow-up letter or telephone call can resolve misunderstandings without needing the formal machinery. If you have a legitimate grievance, consider whether your MP’s office can help—they maintain links with HMRC and can sometimes escalate matters more effectively than individual complaints.

Keep meticulous records of all correspondence. Dates, names, reference numbers, and copies of letters are essential ammunition if your complaint does proceed. If HMRC has caused you financial loss through poor service, document it carefully—this evidence matters at both complaint stages.

Final Thoughts

A formal HMRC complaint is worthwhile when there’s a genuine service failure, documented evidence, and a realistic prospect of a positive outcome. If your issue boils down to disagreeing with how the tax law applies, however, you’re likely to be disappointed. The complaints process works best when you’ve been given poor advice, missed because of HMRC’s delays, or suffered clear procedural failings.

For tailored advice on whether your situation warrants a formal complaint, or help preparing one, contact Severn Accounting — we’re here to help.