What a compliance check looks like
A compliance check is HMRC examining a return in detail. It starts with a letter naming a tax year and asking for specific records, usually the mileage log and the income figures. It is not an accusation, and how it goes depends almost entirely on what you can produce.
Correct for the 2026/27 tax year. Last checked 12/09/2026.
Most drivers will never have one. The ones who do usually find that the outcome was decided long before the letter arrived, by whether they kept records.
How it starts
A letter, naming a tax year and listing what HMRC wants to see. It gives a deadline, usually around thirty days, and a named officer. It is not a demand for money and it does not say you have done anything wrong.
What it usually asks a driver for
- The mileage log for the year, with the basis for the business proportion.
- Odometer readings, or an MOT history showing the total mileage the vehicle did.
- Platform statements for every app you worked on.
- Bank statements for the account the income was paid into.
- Receipts for any expense claimed outside the mileage rate.
What good looks like
A dated log, exported as a file, showing each working day, the distance and the purpose, adding to a figure that reconciles against the odometer and leaves a plausible amount of private mileage. Send that and the check is generally short.
What bad looks like
A single annual figure with nothing behind it. HMRC is entitled to disallow a claim it cannot verify, so the tax on the whole deduction becomes payable, with interest, and a penalty is possible on top depending on why the return was wrong.
Penalties
Penalties for an inaccurate return depend on behaviour: a mistake made despite reasonable care attracts none, carelessness attracts some, and deliberate understatement attracts a great deal. Telling HMRC yourself, before they ask, reduces every one of those.
What to do if a letter arrives
- Read what is actually being asked for. It is usually narrower than it feels.
- Reply within the deadline, even if only to ask for more time. Silence is the one response that makes it worse.
- Send what was asked for, not everything you have.
- Keep a copy of what you sent and when.
- Get an accountant involved if more than one year is named or if a large adjustment is proposed.
A note on framing
This describes how compliance checks generally run. It is not advice on handling your own, and if you are in one with a significant amount at stake, an hour with an accountant is worth considerably more than a web page.
Sources
Common questions
- Why would HMRC check my return?
- Because a figure looks unusual against other drivers, because the platform data it holds does not match what you declared, or at random. A proportion of checks have no trigger at all.
- How far back can HMRC go?
- Normally four years. Six where the return was careless, and up to twenty where HMRC alleges deliberate behaviour. The distinction turns on why the return was wrong, not on how wrong it was.
- Do the platforms tell HMRC what I earned?
- Yes. Digital platforms report earnings data under the reporting rules, so HMRC generally has a figure for what you were paid before it ever writes to you.
- Should I get an accountant for a check?
- If the amounts are large or the letter mentions more than one year, yes. For a simple request for a mileage log on one year, sending the log is usually the whole of it.
- What happens if I cannot produce the records?
- HMRC can reject the claim and recalculate the tax without it. A mileage claim with no log behind it is the most common casualty, and it is often the largest single figure on the return.
About the author
Issac Davies, Founder of JoltMile
Issac Davies drives for gig apps in the UK and built JoltMile to show drivers what a shift actually pays once fuel, insurance and tax come off. Every guide here is checked against HMRC and gov.uk guidance, and is information rather than tax advice.
Track this automatically
Shift log · CSV and JSON export: the JoltMile app works this out from your own shifts. Your first 10 shifts are free.
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