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HMRC internal manual

VAT Assessments and Error Correction

Section 73(1) and 73(2) assessments: Interrelated errors

You should only make assessments to reallocate VAT from one accounting period to another as a result of inter-related errors, where both periods are within four years of the date the assessment is made

For Example: tax point errors - but this exception does not apply to error corrections, see VAEC7340. Where one of the periods is more than three years old, you should not assess for either period to reallocate VAT.