This part of GOV.UK is being rebuilt – find out what beta means

HMRC internal manual

Capital Gains Manual

Absolute entitlement: class closing rules: possible birth of children

There are cases in which the possibility of the birth of children (including further children) to a particular woman is relevant to the question of absolute entitlement. For example, if there is a life interest to Mrs A with remainder to her children, failing whom to B, and Mrs A (who has no children) surrenders her life interest, B does not become absolutely entitled if there is a possibility that Mrs A will have children.