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HMRC internal manual

VAT Assessments and Error Correction

General assessment procedures: Supplementary assessments

Where a re-examination of an assessment indicates that it should have been made for a greater amount, section 77(6) of the VAT Act 1994 provides for a supplementary assessment to be made providing it is made under the same legislative provisions as the original assessment and the time limits applicable to the original have not expired.

Section 77(6) was introduced following the Keith Committee’s recommendation that legislative provision should be made for making assessments when, on re-examination of the same facts it is found that the original assessment was too low.

Note: Taking account of the intention, it is a matter of policy that Section 77(6) is used only where the original assessment was made for too low an amount because of clerical or arithmetical error

For guidance on when to use supplementary assessments, see VAEC6210.