IHTM26203 | Allocating the burden of tax: effect of the rules
From HM Revenue & Customs · Inheritance Tax Manual
The effect of IHTA84/S41 is that:
Any exempt specific gift is paid gross - that is without deduction of tax.
The residue is dealt with as follows
tax on the tax free specific gifts above is deducted from the whole residue
the balance is divided according to the terms of the will or other disposition, and
the tax on the chargeable part of the residue is then borne by that part, even if there are any provisions to the contrary in the Will
But, the burden of tax attributable to a chargeable specific gift which does not bear its own tax may fall on an exempt share of residue. In our view the tax attributable is calculated as follows:
the grossed up value of the specific gift
divided by the total value transferred by chargeable transfer
multiplied by the total tax on that chargeable transfer