What Happens Now?
When business owners say this, it’s usually followed by one question:
“Am I in trouble with HMRC?”
The uncomfortable truth is this.
HMRC does not care who made the mistake.
They care about what was submitted, whether it was correct, and whether tax was underpaid.
If your accountant made an error, the responsibility still sits with you as the business owner or director. That is written into UK tax law and it is enforced in practice.
This is where panic often starts. But this is also where clarity matters more than emotion.
Let’s break down what actually happens, what HMRC looks at, and what you should do next.
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What Counts as an “Accountant’s Mistake”?
An accountant’s mistake is not limited to typing errors.
It includes things like:
Incorrect expenses claimed
Income missed or recorded in the wrong period
VAT errors on returns
Payroll submissions wrong or late
Director loan accounts not monitored properly
Stock, WIP or accruals calculated incorrectly
Tax reliefs claimed without evidence
Some of these mistakes increase tax, some reduce it. HMRC treats both as serious.
Even if the error came from information you provided, HMRC still expects the final submission to be accurate.
Who Is Legally Responsible?
This is the part many business owners misunderstand.
Your accountant acts as your agent, not the responsible party.
Under UK legislation, the taxpayer is responsible for accuracy.
That applies to:
Sole traders
Company directors
Partnerships
Trustees
If HMRC opens an enquiry, they will address it to you, not your accountant.
You cannot defend an error by saying “my accountant did it”.
What Happens When HMRC Finds the Mistake?
HMRC follows a structured process.
First, they assess how the mistake happened.
They categorise errors as:
Careless
Deliberate
Deliberate and concealed
Most genuine accountant errors fall under careless, but that does not mean penalty-free.
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Does HMRC Accept “Reasonable Care”?
Yes. But the bar is higher than most people realise.
HMRC expects you to show that:
You provided complete and accurate information
You reviewed the accounts and tax returns
You asked questions when figures did not make sense
You had systems in place, not guesswork
Signing accounts without understanding them weakens any defence.
This is why “I trusted my accountant” rarely protects you fully.
Can You Claim Against the Accountant?
Possibly. But this is not quick or simple.
Professional indemnity insurance may cover professional negligence, but only where:
The mistake is clearly proven
Financial loss is directly linked
You acted promptly
It does not stop HMRC action.
You still must pay HMRC first. Claims come later.
What You Should Do Immediately
If you suspect an error, timing matters.
The safest route is voluntary disclosure.
When errors are disclosed before HMRC finds them:
Penalties are significantly reduced
The tone of the enquiry changes
Control stays with you
Waiting rarely improves the outcome.
What matters most is getting the numbers right quickly and defensibly.
Why This Keeps Happening
In practice, most “accountant mistakes” are not single errors.
They come from weak foundations:
Poor bookkeeping
No review process
No commercial understanding of the business
Compliance treated as a tick-box exercise
HMRC legislation has tightened.
Digital records, cross-checks, and data matching are now routine.
Errors are easier to spot than ever.
The Real Risk Most Businesses Miss
The biggest risk is not the penalty.
It’s making decisions based on wrong numbers.
Incorrect profits distort:
Cash planning
Dividend decisions
VAT forecasting
Growth plans
Funding discussions
By the time HMRC steps in, the damage is already done.
Final Thought
Mistakes happen. What matters is how fast they are identified and corrected.
If your accounts or tax returns feel unclear, rushed, or unexplained, that is a warning sign.
Clarity protects you.
Structure protects you.
Silence does not.
If you want a proper review of your accounts, tax position, and exposure under current HMRC rules, get experienced support now.
Correcting problems early is always cheaper than defending them later.
Book a Discover Call: https://calendly.com/skynet-skynetaccounting/new-meeting
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About the Author
Written by Yesim Tilley Founder of Skynet Accounting is a chartered accountant with over 20 years of experience supporting manufacturing and engineering businesses across the UK. Specialising in cost analysis, product costing, and financial strategy, she helps industrial businesses understand their numbers and make more profitable and sustainable decisions. Skynet Accounting provides tailored finance, compliance, and taxation support for business owners.