Self Assessment late-payment penalty (UK)
Under the 2025–26 Self Assessment rules, late-payment penalties can arise at 30 days, six months and 12 months, each generally 5% of the tax still unpaid at that point. Interest is separate, and statutory exceptions, reasonable excuse and payment arrangements may affect the result. Filing penalties have separate rules.
Worked example
A taxpayer has £2,000 of Self Assessment tax still unpaid at the 30-day penalty point. Assuming no exception or payment arrangement applies, the first 5% penalty is £100; later penalties and interest are considered separately.
Common mistake
Confusing late-payment penalties with late-filing penalties or applying 5% to tax already paid before the relevant penalty point.
Where it appears in your exams
| Qualification | Exam | Relationship | Period |
|---|---|---|---|
| ACCA | TX (UK) | Direct | June 2026–June 2027 |