VAEC2220 | Types of assessment: Prime assessments information: Manual calculation of assessment
From HM Revenue & Customs · VAT Assessments and Error Correction
For information about retired VAT systems, go to VAEC0150. For information about Making Tax Digital for VAT and ETMP processes, go to VAEC0200.
Where a prime assessment is to be calculated manually, you should
refer to any relevant information held in respect of the trader
if there is insufficient information available the trader should be contacted, preferably by telephone, in an attempt to obtain the return or establish an amount for the assessment
calculate the assessment based on the available information, and
complete form VAT152A Notice of Assessment, following the procedures at VAEC2510.