What is a step child - inheritance tax

[emlach1ka]

If a woman marries a man whilst her children are very young, then divorces him 20 years later, will these children, whom are adults now, still be classed as step children in the eyes of the law when it comes to the inheritance tax threshold?

[maths]

I assume you are referring to the newly introduced "residence nil rate band".

Assuming so, then once a step-child always a step-child.