VAT return mistakes that trigger an HMRC enquiry (and how to avoid them)

Why HMRC notices some returns and not others

HMRC doesn't read every VAT return by hand. It runs them through risk checks that look for patterns — figures that don't add up, claims that look unusual, numbers that swing wildly from one quarter to the next. When something trips a flag, you can get a "compliance check," which is HMRC's polite term for an enquiry: questions, document requests, and in the worst case, penalties and interest.

The reassuring truth is that the returns which get flagged are rarely sophisticated fraud. They're ordinary, honest mistakes — the same handful, over and over, made by founders doing their best with a form they were never trained to fill in.

So if you know the usual traps, you can sidestep nearly all of them. Here are the big ones, why they happen, and how to make sure they never reach HMRC on your return. (New to VAT entirely? Start with What is VAT and do I actually have to charge it? →.)

Mistake 1: reclaiming VAT on entertainment

This is the single most common error, and it's an easy one to make.

You take a client to lunch, the bill has VAT on it, and you reclaim that VAT like you would any other expense. Feels reasonable. But VAT on business entertainment — wining and dining clients, prospects, contacts — generally can't be reclaimed, even though you genuinely paid it. HMRC treats it as a non-recoverable cost.

It's a tempting mistake because the receipt does show VAT, and your instinct is "VAT paid, VAT reclaimed." The line that catches people is the difference between staff costs (some of which can be reclaimable) and client entertainment (which generally can't). Get it wrong repeatedly and it stands out — entertainment-style suppliers showing up in your reclaim is exactly the kind of pattern checks look for.

How to avoid it: flag entertainment spend separately so it never lands in your reclaimable pile by accident.

Mistake 2: the wrong VAT rate on a transaction

Not everything is 20%. Some goods and services are reduced-rated, some are zero-rated, some are exempt, and the differences matter. Put a transaction on the wrong rate and you've either over-reclaimed, under-charged, or misreported your totals — all of which distort your return.

This happens most when you're typing figures yourself, or when a supplier's invoice is ambiguous and you guess. One wrong rate on a big invoice can move your Box 4 enough to look odd. Multiply it across a quarter and the return drifts away from reality without you noticing.

How to avoid it: apply rates consistently and have something check that the rate on each transaction makes sense for that kind of supplier — not just that a rate was applied.

Mistake 3: missing the reverse charge

This one trips up more businesses every year, and it's the kind of thing that sounds made up until it bites you.

For certain transactions — most commonly digital services bought from overseas suppliers, and construction work under the CIS domestic reverse charge — the normal VAT flow is inverted. Instead of the supplier charging you VAT, you account for both the output and input VAT on your own return. It nets to zero in cash terms, but it absolutely has to appear on the return.

Founders miss it because nothing on the supplier's invoice prompts them — there's no VAT line to copy. So the entry just... doesn't get made. HMRC, however, can see the mismatch, and missing reverse-charge entries are a known red flag, especially for software-heavy startups buying overseas tools and for anyone in construction.

How to avoid it: recognise which transactions need the reverse charge and make sure the entry is created, even though the invoice doesn't shout about it.

Mistake 4: round-sum guessing

If your return is full of suspiciously tidy numbers — £2,000 of VAT here, £500 there, totals that end in round hundreds — it reads as estimated rather than calculated. Real trading throws off messy figures: £1,847.36, £213.09. Round-sum returns suggest someone reached for a plausible number instead of adding up what actually happened.

This usually comes from filing under time pressure, with incomplete records, plugging gaps with "that's about right." It's understandable and it's dangerous — guessed figures are wrong figures, and consistently round ones invite a closer look.

How to avoid it: build the return from your actual transactions, every one of them, so the totals come out as messy as real life — because that's what truthful returns look like.

The hard way today: why these slip through

Here's the uncomfortable part. Spreadsheets and most accounting software won't stop you making any of these mistakes.

A spreadsheet does exactly what you type. Reclaim entertainment VAT, apply the wrong rate, skip the reverse charge, round a number — the spreadsheet nods along and totals it up. It has no opinion about whether the answer is sensible.

Tools like Xero are a step better — they pull from your bank feed and build the return — but they largely trust the categorisation they're handed. If a restaurant bill got coded as a normal reclaimable expense, Xero reports the reclaim, confidently. It rarely stops to say "wait, that's entertainment — are you sure?" The software does the arithmetic reliably. It doesn't do the judgement. And judgement is exactly where these four mistakes live.

So you're left as the last line of defence, checking for errors you may not know to look for. That's not a personal failing. It's a tooling gap.

How the anomaly checker catches them in Ledgers

This is the job the anomaly checker in Ledgers is built for — being the second pair of eyes you don't have.

Before any VAT return goes to HMRC, Ledgers runs anomaly checks across the whole thing, looking for exactly the patterns above:

• Entertainment reclaims. Spot a restaurant or hospitality supplier sitting in your reclaimable VAT, and it flags it — "this looks like entertainment, VAT usually isn't reclaimable here, check it."
• Odd VAT rates. A transaction on a rate that doesn't fit that type of supplier gets surfaced so you can confirm it's right rather than discovering later that it wasn't.
• Missing reverse charge. Overseas digital-service suppliers and construction transactions that look like they need the reverse charge — but don't have the entry — get flagged before you file.
• Round-sum and out-of-line figures. Numbers that are suspiciously tidy, or wildly different from last quarter, get raised so you can check the working instead of submitting a guess.

Because your books are built continuously from your bank feed and reconciled line by line, the return starts from real, messy, accurate numbers — not estimates. The anomaly checker then reads it the way an experienced bookkeeper would, hands you a short list of "have a look at these," and only once you've signed off does it submit to HMRC, Making Tax Digital compatible and digitally linked. And because nothing disappears on the event-sourced ledger, every figure traces back to the transaction behind it — so if HMRC ever does ask, you can show your working instantly.

What you'd actually see

You finish your quarter and open the VAT return. Five flags. One: "£96 VAT reclaimed on a hospitality bill — entertainment VAT usually isn't reclaimable." Two: "AWS invoice from a US supplier — possible reverse charge not recorded." Three: "Box 4 is 40% higher than last quarter — confirm." You click through each: fix the entertainment one, add the reverse-charge entry, and confirm the Box 4 jump is real because you bought a lot of kit this quarter.

Three minutes. Three mistakes that would have stood out to HMRC, gone before they ever reached it. You sign off and submit, knowing the risky lines were checked — not hoping they were.

That's the whole point. You don't avoid an enquiry by being a VAT expert. You avoid it by having something that catches the usual mistakes before you press submit.

A note on rules, rates and thresholds

VAT rules shift, and the detail around entertainment, rates and the reverse charge has real nuance — so treat this as a map, not the territory, and confirm specifics with HMRC. As of writing, the standard rate is 20% and the registration threshold is £90,000 of taxable turnover over a rolling 12 months. For the current position on any particular cost or rate, the official source is always HMRC's VAT guidance.

The best way to avoid an HMRC enquiry is to never submit the mistake in the first place. In Ledgers, the anomaly checker reads your VAT return before you do — flagging entertainment reclaims, wrong rates, missed reverse charges and round-sum guesses — then submits to HMRC once you've signed off. See your numbers without learning accounting → start free.

Filing your first one? Here's the gentle walkthrough: How to do a VAT return for the first time →

Want the full step-by-step? How to file a VAT return (without an accountant) →

Frequently asked questions

What are the most common VAT return errors?

Reclaiming VAT on client entertainment (which usually isn't allowed), putting transactions on the wrong VAT rate, missing the reverse charge on overseas digital services or construction work, and filling the return with round-sum guesses instead of actual figures. These are the errors most likely to get noticed.

Can you reclaim VAT on entertainment?

Generally no. VAT on business entertainment — hosting clients, prospects or contacts — usually can't be reclaimed, even though you paid it. Some staff-related costs differ. Confirm the current position with HMRC, and flag entertainment spend separately so it doesn't slip into your reclaim by accident.

What is the VAT reverse charge and why does missing it matter?

For certain transactions — commonly overseas digital services and CIS construction work — you account for both the input and output VAT yourself instead of the supplier charging it. It nets to zero in cash, but it must appear on your return. Missing it is a known HMRC red flag because the mismatch is visible to them.

Will a small VAT mistake trigger an HMRC enquiry?

A single small error usually won't, and many can be corrected on a later return. But repeated mistakes, large discrepancies, or patterns like round-sum figures and odd reclaims raise your risk. Catching errors before you submit — with anomaly checks — is far easier than untangling an enquiry afterwards.

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