Compliance
How Recent Penalty Reforms Affect Self Assessment & Corporation Tax
Budget 2025 brought in sweeping changes to penalties for late Self Assessment and Corporation Tax returns — learn what those are, when they take effect, and how to avoid costly fines.
By NomadicTax Research Team • 5-8 min read • August 27, 2026
## Key Penalty Changes from Budget 2025
Budget 2025 introduced reforms that affect **Corporation Tax late filing penalties** and the penalty regime for **Self Assessment (SA)** and **VAT**, particularly where Making Tax Digital (MTD) is involved. ([gov.uk](https://www.gov.uk/government/publications/budget-2025-overview-of-tax-legislation-and-rates-ootlar/budget-2025-overview-of-tax-legislation-and-rates-ootlar?utm_source=openai))
### Corporation Tax Late Filing Penalties
For Corporation Tax returns due **on or after 1 April 2026**, penalties have roughly **doubled** in many cases:
- Late return: increased from **£100 to £200**
- More than **3 months late**: from **£200 to £400**
- **Three successive failures**: from **£500 to £1,000** (return late) or **£1,000 to £2,000** (more than 3 months late) ([gov.uk](https://www.gov.uk/government/publications/budget-2025-overview-of-tax-legislation-and-rates-ootlar/budget-2025-overview-of-tax-legislation-and-rates-ootlar?utm_source=openai))
### Self Assessment & VAT Penalty Reform
The reforms introduce a **points-based system** for late submissions under MTD for Income Tax. Key aspects:
- For the **2026-27 tax year**, though quarterly updates are mandatory for those with income over £50,000, **no penalty points** will be issued for missing those updates. ([gov.uk](https://www.gov.uk/government/news/436000-sole-traders-and-landlords-make-their-tax-digital?utm_source=openai))
- If you’re mandated for MTD, the new penalty regime for late submission and late payment applies from when you join; those not yet mandated will transition from **6 April 2027**. ([gov.uk](https://www.gov.uk/government/publications/summary-of-tax-update-2026-simplification-modernisation-and-fairness/tax-update-2026-simplification-modernisation-and-fairness-summary?utm_source=openai))
- From 6 April 2027, missing deadlines will accrue penalty points; after **4 points**, you’ll incur a **£200 fixed penalty**, with additional financial penalties or interest for payment failures. ([gov.uk](https://www.gov.uk/government/news/436000-sole-traders-and-landlords-make-their-tax-digital?utm_source=openai))
## Implications and Risks for Businesses & Individuals
- **Increased financial exposure**: Bigger penalties for companies missing Corporation Tax deadlines, especially for repeat failures.
- **MTD compliance becomes critical**: Moving to digital updates and submission means missing quarterly deadlines will now carry consequences in future years.
- **Complexity in transition**: For those not yet mandated or in early years of MTD, tracking when penalties or points apply will require careful attention.
## Examples
- **Example 1:** A medium-sized company misses its Corporation Tax filing for a return due May 2026. Before, a £100 penalty; post-4/1/2026 it’s £200. If it's a third successive failure, the penalty could reach £1,000.
- **Example 2:** A sole trader with income over £50,000 omits to send a quarterly update due in August 2026. No penalty points this year, but must catch up to avoid points later.
## How to Handle the Changes
- Use **calendar tools and reminders** for all filing dates, especially quarterly updates and SA deadlines.
- **Engage an agent or accountant** if unsure — especially for businesses moving into MTD or those used to the previous regime.
- **Document everything**: if you miss a deadline, having a “reasonable excuse” matters in appeals.
- Keep an eye on **HMRC consultations**, factsheets, and guidance updates — reforms are still evolving.
## Conclusion
These reforms represent HMRC’s push toward modernisation, fairness, and better tax compliance. The stakes are higher: for companies with larger fines, and for individuals mandated into MTD with points-based penalties. Stay organised, stay informed — and don’t allow deadlines to slip.