Built on HMRC's own reasonable-excuse test

Don't just pay it.
Flip it.

Enter your HMRC penalty and get a formal appeal letter citing the exact legislation and case law that overturns fines — grounded in the Perrin v HMRC reasonable-excuse test.

Free to checkNo sign-up£19.99 one-off
HMRC penaltyNotice SA326

What you owe

£100
Initial late-filing penalty£100
Daily penalties (90 × £10)+£900
6-month tax-geared penalty+£300
Escalates every month you wait

Penalty

£1,300

Grounds to appeal

£0

if your appeal succeeds

  • Reasonable-excuse test met
  • Cites FA 2009 Sch 55 & Perrin v HMRC
Check my grounds — free

HMRC penalties escalate over time. A £100 fine can become £1,300+ after 6 months — and your 30-day appeal window is ticking.

Everything you need to overturn it

The penalty is the problem. The flip is the product.

Do nothing

How a £100 fine becomes £1,600

Day 1
£0

Initial late-filing penalty

3 months
£0+£900

Daily penalties, £10 × 90 days

6 months
£0+£300

Tax-geared penalty kicks in

12 months
£0+£300

A further tax-geared penalty

Appeal in time and the whole stack can be overturned.

One price

£19.99

one-off — not a subscription

  • Full formal appeal letter
  • Correct legislation cited
  • Perrin v HMRC test addressed
  • Sending instructions & deadlines
Check free first

See your grounds before you pay.

How it works

Three steps to a professional appeal

  1. Step 1

    Check free

    Describe what happened in plain English. We assess your grounds instantly — no sign-up.

  2. Step 2

    See your grounds

    We identify the legislation and reasonable-excuse arguments that apply to your penalty.

  3. Step 3

    Get the cited letter

    A formal, statute-cited appeal ready to submit online or post with form SA370.

A note on Making Tax Digital (MTD for Income Tax)

TaxFlip covers traditional Self Assessment, VAT, Corporation Tax and PAYE penalties. The new MTD-ITSA regime uses a separate points-based system for late quarterly updates — those penalties work differently, so check the penalty type on your notice before you appeal.

Check my penalty type

Common questions

Straight answers before you spend a penny

Yes. If you have a reasonable excuse — such as serious illness, bereavement, fire, flood, IT failure, or HMRC's own error — you can appeal within 30 days of the penalty notice. Over a million penalties are issued each year, and many are successfully appealed.

HMRC accepts: serious illness or disability, bereavement, fire or flood, computer or software failure, postal delays, HMRC errors, and mental health conditions. They do not accept 'I forgot', 'I was too busy', 'I didn't know about the deadline', or 'I couldn't afford to pay'.

TaxFlip identifies your penalty type (late filing, late payment, VAT, Corporation Tax, PAYE) and applies the correct legislation — Taxes Management Act 1970, Finance Act 2009 Schedule 55/56, or VAT Act 1994 — and addresses the Perrin v HMRC reasonable-excuse test.

No. TaxFlip generates appeal letters based on publicly available UK tax legislation and established case law. It does not constitute formal legal advice. For complex cases or tribunal appeals, we recommend consulting a chartered tax adviser or solicitor.

HMRC aims to respond within 45 days. If they accept your appeal, the penalty is cancelled. If they reject it, you can request a statutory review by a different HMRC officer, or appeal to the First-tier Tribunal (Tax Chamber) — which is free and independent of HMRC.

You can try. If you have a good reason for the late appeal — such as not receiving the penalty notice, or ongoing illness — HMRC may still consider it. TaxFlip will include a paragraph explaining the late appeal if applicable.

Don't just pay it. Flip it.

Most people pay HMRC penalties they could have overturned. TaxFlip gives you the same legal arguments a chartered adviser would use — for £19.99, one-off.

Free assessment. No sign-up. Takes about 2 minutes.