# What happens if I file my tax return late?

Pick My Accountant (https://pickmyaccountant.co.uk/answers/what-happens-if-i-file-my-tax-return-late/): What happens if I file my tax return late? — Quick answer. Miss the 31 January online deadline and HMRC charges £100 immediately — even if you owe no tax. After three months, £10 daily penalties (up to £900) begin; at six and twelve months, further penalties of £300 or 5% of the tax due, whichever is higher. Late payment adds separate 5% surcharges at 30 days, 6 months, and 12 months, plus daily interest. Filing something — even late — always beats waiting.

## Key facts

- £100 fixed penalty the moment the deadline passes, regardless of tax owed
- 3 months late: £10/day for up to 90 days (max £900) on top
- 6 and 12 months late: £300 or 5% of tax due each time, whichever is higher
- Late payment is penalised separately: 5% of unpaid tax at 30 days, 6 months, and 12 months, plus interest
- Reasonable-excuse appeals succeed for genuine cases: serious illness, bereavement, HMRC failures

## How do HMRC late-filing penalties escalate?

A return that's a year late with £5,000 owed racks up roughly: £100 fixed + £900 daily penalties + two further penalties of at least £300 each — over £1,600 in filing penalties alone, before the three separate 5% late-payment surcharges (£750) and interest. The system is deliberately front-loaded so the cheapest moment to act is always now: each threshold you cross adds a new, unavoidable layer.

## Should you file even if you cannot pay?

Filing and paying are penalised separately — so filing on time with an unpaid bill avoids the entire filing ladder. Then call HMRC (or apply online) for a Time to Pay arrangement, typically spreading the bill over months; a plan set up before the payment surcharge dates prevents the 5% hits, though interest still runs. The worst strategy is silence: penalties compound and HMRC can eventually estimate your tax for you at an unflattering figure.

## Can you appeal a late-filing penalty?

You can appeal any penalty within 30 days if you have a reasonable excuse — serious illness, bereavement close to the deadline, fire or flood, or HMRC's own system failures. Pressure of work, a slow accountant, or not knowing the rules don't qualify. If the excuse is genuine, appeal in writing with evidence; accountants routinely get fair penalties overturned, and even unfair daily penalties reduced.

## Does an accountant prevent late-filing penalties?

One £100 penalty is more than two months of a typical sole trader package — and a 12-month spiral costs a year of fees. If you've already missed a deadline, a firm can file quickly, negotiate Time to Pay, and handle the appeal; if you haven't, the calendar ownership alone justifies the retainer for most busy owners. Try our penalty calculator to see your current exposure, then compare firms.

## FAQs

**Q: Do penalties apply if I'm owed a refund?**
A: Yes — the £100 fixed penalty and daily penalties apply even when no tax is due, which feels outrageous and is nonetheless the law. The tax-geared 6- and 12-month penalties have a £300 minimum for the same reason.

**Q: What about a late corporation tax return?**
A: Companies face a separate ladder: £100 late, another £100 at three months, then 10% of unpaid tax at six and twelve months — and repeated lateness doubles the fixed penalties. Companies House charges its own penalties for late accounts on top.

**Q: Will HMRC really charge interest on top of penalties?**
A: Yes — late payment interest runs daily on unpaid tax and on unpaid penalties, at a rate linked to the Bank of England base rate. It's not negotiable, which is why Time to Pay early is worth arranging.

Updated: 2026-08-13

Source: https://pickmyaccountant.co.uk/answers/what-happens-if-i-file-my-tax-return-late/