IHTM36172 | Calculating the penalty: effect of criminal proceedings
From HM Revenue & Customs · Inheritance Tax Manual
Any case in which criminal proceedings have been taken will usually be settled by SpecialCivil Investigations. However, it will be returned to you with instructions if,exceptionally, you are to negotiate a settlement. In general
you will not be able to claim a civil financial penalty on the basis of fraud (IHTM36291) in respect of an offence which has been before the criminal courts
you will be given advice on whether to claim a penalty based on negligence (IHTM36301) from a taxpayer who has been acquitted of fraud
you should claim a penalty in the normal way in respect of any offence which did not form part of the criminal proceedings.