IHTM12174 - Distributions under intestacy (NI): issue
Subject to the rights of the surviving spouse or civil partner ( IHTM11032) ( IHTM12171) the issue (children, grandchildren and remoter descendants) take absolutely in the following order
- the deceased’s children living at the death in equal shares on attaining 18 or marrying under that age.
- the grandchildren (or remoter descendants) living at the death whose parent would have taken a share but for dying before the intestate, in equal shares of their parent’s share on attaining 18 or marrying.

You should note that
- adopted children have the same rights as natural children
- legitimated children are entitled as if they had been born legitimate
- an illegitimate child can benefit from a parent’s estate and they from the child's
- step children are not issue unless they have been adopted by the deceased.
