This is general guidance, not personalised tax advice. Compliance check procedures and penalty rules change — check gov.uk or your accountant if you're actually facing one.
HMRC compliance checks on self-employed tradesmen aren't usually triggered by bad luck — they're increasingly triggered by data. Figures that sit well outside the range HMRC expects for a given trade and turnover, a sudden year-on-year jump or drop in reported income, or an industry-wide "one to many" letter campaign targeting a specific trade or scheme can all put a return under review. CIS sub-contractors are a frequent focus, since HMRC can cross-reference contractor returns against sub-contractor declarations directly.
How a check actually starts
Most compliance checks begin with a letter, not a knock on the door — a request for specific records supporting a particular year's return, sometimes narrow (just one category of expense) and sometimes broad (the full set of business records). The letter will specify a deadline to respond, and ignoring it doesn't make the check go away; it escalates it.
What "no receipts" actually costs you
Without records, HMRC doesn't simply take your word for expenses claimed — they can disallow them entirely, or substitute their own estimate of what's reasonable, which is rarely generous. The tax, interest, and penalty due then gets calculated on a version of your accounts you didn't produce and can't easily argue against, because you have nothing to argue with.
How penalties actually scale
HMRC categorises errors by behaviour, and the penalty percentage follows the category: a genuine, careless mistake carries a lower penalty than one deemed deliberate, and a deliberate error that's also concealed carries the highest. Full, unprompted disclosure the moment a gap is found — rather than waiting to be caught — generally attracts a lower penalty than the same gap discovered by HMRC itself. This is one of the few places where acting first genuinely changes the outcome.
How far back they can go
For an ordinary careless error, HMRC can generally go back four years. Where the behaviour is judged careless in a more serious sense, that extends to six years. Where it's deemed deliberate, HMRC can go back up to twenty years — a very different scale of exposure, and exactly why "I probably had records somewhere" isn't a defensible position if a check ever actually lands.
What actually protects you
- Digital records that survive — a photo in a camera roll that's since been deleted or a paper receipt that's faded to nothing is functionally the same as never having kept it.
- Records tied to a specific job or claim — a bank statement showing a payment to a merchant doesn't itself prove what was bought or that it was for the business; the itemized receipt does.
- Consistency across years — a sudden change in reported expense patterns with no obvious business reason is exactly the kind of anomaly that draws attention in the first place.
How Site Wallet helps here
Every receipt scanned is dated, itemized, tagged to a job and kept encrypted for as long as you need it — not dependent on a phone's camera roll surviving, or a thermal receipt not fading before it's needed. If a compliance check ever does land, a full export by tax year is a few taps, not a search through years of paperwork that may or may not still exist.
FAQ
How likely is a compliance check, realistically?
Most sole traders never face one, but the trades most exposed to CIS cross-referencing and industry benchmarking are more likely to see a check than the average small business — it's not worth relying on the odds.
Can I use bank statements instead of receipts?
They can support a case but don't replace a proper receipt — a bank statement shows money left your account, not what it was for or that it was a genuine business cost.
What should I do the moment I realise records are missing?
Talk to an accountant about a voluntary disclosure before HMRC finds the gap itself — unprompted disclosure is treated more favourably than the same issue found during a check.