The rules of intestacy.

Unmarried, widowed or divorced?

If you have children everything passes to them at 18.

If no children but you have parents then everything to them equally.

If no children or parents then everything to brothers and sisters of the whole blood absolutely. 

If there are no brothers or sisters of the whole blood, then to brothers and sisters of the half blood equally.

If there are no relatives listed above but grandparents survive then everything to those grandparents equally.

If there are no relatives listed above and no grandparents survive then everything to uncles and aunts of the whole blood equally.