Can I Sue My Accountant for Negligence? (UK)

When an accountant's mistake becomes a legal claim

Accountants owe their clients a duty to act with the skill and care of a reasonably competent member of the profession. A claim arises when they breach that duty and the breach causes a financial loss. Being unhappy with the outcome is not enough — there must be a genuine failure, and a loss that flowed from it.

The failures we see most often

Accountant negligence is not exotic. The claims that succeed most commonly involve:

• Missed filing deadlines producing HMRC penalties and interest
• Incorrect tax returns triggering HMRC enquiries and assessments
• Negligent tax planning or structuring that unravels under scrutiny
• Failure to claim reliefs, allowances or repayments you were entitled to
• Wrong advice on VAT, capital gains, dividends or company structure
• Errors in accounts relied on for a sale, purchase or loan

The three things you must prove

First, the duty: what the accountant was engaged to do. The engagement letter is the starting point, but the actual scope of the work matters too. Second, the breach: the specific point where the work fell below professional standards — which usually takes an independent accountancy opinion to establish. Third, causation and loss: that the failure, rather than the market or your own decisions, produced a quantifiable loss.

Most claims are won or lost on the second and third points, which is why a proper assessment starts by reconstructing exactly what the accountant was asked to do and what they actually did.

Time limits — and why you should not wait

Limitation in professional negligence is fact-specific: broadly six years from the breach or the damage, with a possible three-year extension from the date you could reasonably have discovered a hidden problem. Because accountancy losses often surface late — an HMRC letter two years after the filing — the clock is not always obvious. Get the position checked early; waiting is the single most common way viable claims die.

What a claim is worth

Damages aim to put you in the position you would have been in had the work been competent: typically the penalties, interest and additional tax you paid, the relief you lost, or the diminution in value of a transaction — plus the wasted fees in many cases. A realistic valuation is part of any proper initial assessment.

First steps

Gather the engagement letter, the returns or advice in question, your correspondence with the accountant, and every HMRC notice or penalty. Then have the file assessed by someone independent. Our assessment is free, and where the claim is not viable we will tell you plainly rather than run up costs.

Common questions