IPT03350 | Overview and the law: value of a premium for IPT purposes
From HM Revenue & Customs · Insurance Premium Tax
Section 50(1) of the Finance Act 1994 states:
Tax shall be charged by reference to the chargeable amount.
Section 50(2) describes the chargeable amount (where no part of a premium relates to a risk which is exempt from IPT) as:
…such amount as, with the addition of the tax chargeable, is equal to the amount of the premium.