VATF45180 | Basic interventions: matters to consider when determining whether to use a civil intervention: assessments and penalties: raising penalties in particular circumstances: calculating the penalty
From HM Revenue & Customs · VAT Fraud
The basic penalty before mitigation is 30% of the ‘potential lost VAT’.
Potential lost VAT is defined as:
Any additional VAT which becomes payable as a result of HMRC’s denial decision plus
Any VAT which is not repaid as a result of that decision