IHTM04344 | Estate Duty surviving spouse exemption: application to lifetime events
From HM Revenue & Customs · Inheritance Tax Manual
The relief is extended to cover lifetime events, where the interest of the surviving spouse terminates during his or her lifetime. The latter part of means that tax is not charged under on the coming to an end () of an interest in possession (IIP) () in settled property if
the spouse (or former spouse) of the person beneficially entitled to the interest died before 13 November 1974, and
the value of the property in which the interest subsists would by virtue of the preceding provisions () of have been left out of account () in determining the value of the survivor’s estate had they died immediately before the interest came to an end.