HMRC compliance checks
What does a tax investigation cost in fees?
Professional representation for a single-aspect HMRC enquiry commonly costs £500–£1,500, and a full enquiry £1,500–£5,000 or more (typical 2026 quotes); complex cases, including Code of Practice 9, cost substantially more. Most compliance checks are routine and end without penalty, so the sensible first step is understanding what you are in, then deciding what help, if any, it needs. Tell us about the enquiry and relevant specialists will quote their fee.
0–100%
HMRC penalty range as a percentage of extra tax due, set by behaviour; nil where reasonable care was taken
Three steps
- Tell us what HMRC has sent and where things stand. Two minutes, no account, no judgement.
- We pass your details to relevant tax investigation specialists, and to no one else.
- They contact you directly, usually starting with a short call, and quote a fee for handling it. Compare, choose, or handle it yourself.
Tax Investigation Cost is a free introduction service operated by Ellul Solutions Ltd; we pass your details to relevant tax investigation specialists who contact you directly. We may receive a fee from providers; you pay nothing and are under no obligation. We are not accountants, tax advisers or solicitors and nothing here is tax or legal advice; fee figures are typical 2026 quote ranges that vary by complexity, and penalty outcomes depend on the facts of each case.
Typical tax investigation fees, 2026
Last updated
What professional representation in an HMRC enquiry typically costs. These are typical quote ranges observed across the UK market in 2026, not fixed fees; the enquiry's scope, the state of the records and how long correspondence runs move the figure.
Ranges reflect typical adviser quotes for HMRC enquiry work observed across the UK market in 2026; they vary by region, complexity and how the enquiry unfolds. Fees are the adviser's charges only: any extra tax, interest or penalties are separate and depend on the facts of the case. Penalty percentages are HMRC's published behaviour-based ranges (gov.uk). Get exact fee quotes for your enquiry via the form above.
| Situation | Typical adviser fee (2026 quotes) | Notes |
|---|---|---|
| Single-aspect enquiry (one or two specific entries queried) | £500–£1,500 | Often resolved in a few letters; simple aspect enquiries can reasonably be handled yourself |
| Full enquiry into a return (individual or small business) | £1,500–£5,000+ | Records review, correspondence, meetings where needed, negotiation of any settlement |
| Complex cases, including Code of Practice 8 or 9 | Substantially more, scoped per case | COP9 (suspected serious fraud, Contractual Disclosure Facility) needs specialist representation; fees reflect the stakes |
| Fee protection insurance (often bundled with accountancy packages) | Commonly modest per year, often included | Covers professional fees for handling an enquiry, not the tax itself; check what your accountant's package already includes |
- Professional fees for a full HMRC enquiry into an individual or small business commonly run £1,500–£5,000+, and a single-aspect enquiry £500–£1,500 (typical 2026 quotes).
- HMRC penalties are behaviour-based percentages of the extra tax due, up to 100% for deliberate and concealed inaccuracies (higher for some offshore matters), and can be nil where reasonable care was taken (gov.uk).
- Fee protection insurance covering enquiry representation costs is often bundled with accountancy packages; many people are covered without realising it.
Cite this page
“Typical tax investigation fees, 2026”, Tax Investigation Cost, https://taxinvestigationcost.co.uk/ (updated 2026-08-14). Ranges reflect typical adviser quotes for HMRC enquiry work observed across the UK market in 2026; they vary by region, complexity and how the enquiry unfolds. Fees are the adviser's charges only: any extra tax, interest or penalties are separate and depend on the facts of the case. Penalty percentages are HMRC's published behaviour-based ranges (gov.uk). Get exact fee quotes for your enquiry via the form above.
Read next
The longer answers, with sources.
Straight answers
How much does a tax investigation cost?
In adviser fees: commonly £500–£1,500 for a single-aspect enquiry and £1,500–£5,000+ for a full enquiry (typical 2026 quotes); complex and COP9 cases cost substantially more. Any extra tax, interest and penalties are separate and depend entirely on the facts of the case.
What are the penalties in a tax investigation?
Behaviour-based percentages of the extra tax due: nil where reasonable care was taken, rising through careless and deliberate categories up to 100% for deliberate and concealed inaccuracies, with higher maximums for some offshore matters. Cooperation and the quality of disclosure reduce the figure within each band (gov.uk penalties guidance).
Do I need an accountant for an HMRC enquiry?
Not always. A simple aspect enquiry about specific entries can reasonably be handled yourself with good records. Representation earns its fee in full enquiries, penalty discussions, and anything under Code of Practice 8 or 9, where specialist help is the settled consensus, including in HMRC's own code.
What is Code of Practice 9?
HMRC's procedure where serious tax fraud is suspected. It offers the Contractual Disclosure Facility: a complete disclosure of deliberate irregularities in exchange for HMRC not pursuing criminal investigation of the disclosed conduct. It has a fixed response deadline and is the clearest case for specialist representation.
Is tax investigation insurance worth having?
It covers adviser fees, never the tax, and is often already bundled with accountancy packages, so check what you have before buying. Whether standalone cover is worth it is an exposure question: rational if a surprise £1,500–£5,000 fee would strain you, equally rational to self-insure if it wouldn't.
Is this quote service really free?
Yes, free to you, with no obligation to engage anyone. We pass your details only to relevant tax investigation specialists, who contact you directly; we may receive a fee from those providers, which is how the service is funded.