01
Quantify before choosing the route
HMRC guidance distinguishes errors that may be adjusted on a later VAT return from errors that must be separately notified. The size, relation to turnover and whether the error was deliberate all matter.
- Four-year correction window in the general guidance
- Netting output and input tax errors
- Turnover-based threshold test
- Separate notification where required
02
The explanation matters
A disclosure should explain what happened, periods affected, calculation method, corrective treatment and steps taken to prevent recurrence. It should not guess at facts that can be verified.
- Error schedule
- Supporting documents
- Behaviour analysis
- Control remediation
Primary sources
Tax guidance changes. These official sources were checked on 31 August 2026.
Correct errors in a VAT ReturnKeeping VAT records