IHTM31512 | Assessing: calculating interest: simple cases
From HM Revenue & Customs · Inheritance Tax Manual
In most cases you can simply charge interest on:
the tax now due
from the due date ()
to the date of the calculation.
But you will have to reduce the interest charge where:
there are deposits () on account to use against the tax, or
the estate contains newly advised Income Tax or Capital Gains Tax repayments ().