CH124620 | Offshore matters: penalties for enablers of offshore tax evasion or non-compliance: calculating the penalty: how to calculate amount of penalty
From HM Revenue & Customs · Compliance Handbook
If both conditions A and B are met, see CH124400, a penalty is chargeable on an enabler.
To calculate the penalty to be charged HMRC officers will need to establish:
When calculating the penalty for the enabler, the potential lost revenue (PLR) for the enabler will be equal to the PLR for the person they enabled, which was the result of that person’s offshore tax evasion or non-compliance. See CH124630, for guidance on calculating the PLR.
Also see CH124610, for the standard penalty rates.