IHTM15031 | The extent of the share: joint property passing by survivorship
From HM Revenue & Customs · Inheritance Tax Manual
Where the joint property passes by survivorship (IHTM15081):
The deceased’s share will be a separate title or fund from the free estate for the purposes of grossing-up (IHTM26121)
In most cases each joint owner’s beneficial entitlement (including that of the deceased) will be an equal share of the whole property. For example, if there were three joint owners the deceased’s beneficial interest would be one third of the asset. There are some exceptions to this which are:
In certain Scottish cases where there is a special destination (IHTM15050).
In England Wales and Northern Ireland each joint owner’s share can be referred to as their ‘severable share’ as it would be the share each owner would be entitled to if they had severed (IHTM15082) the joint tenancy. But this does not apply to joint property in Scotland.