IHTM26083 | Step 1 - the starting value of specific gifts: settled gift

From HM Revenue & Customs · Inheritance Tax Manual

Property may be settled by a specific gift (IHTM26011), either

by giving a person a qualifying interest in possession (IHTM16061), such as a life interest to a surviving spouse or civil partner (IHTM11031) (IHTM11032), or
on relevant property trusts (IHTM42161).

In these situations the value of the gift for the purposes of the partly exempt transfer rules (IHTM26071) is the value of the property settled.