hi ya

I believe that some time ago in the uk, it was not uncommon in divorce
settlements for the partner who did not get custody of the children
involved,
never to be able to see their children again. This was not for any
reason due to the partner been violent or abusive towards their
children. (in a case of a friend , it was OK for him to see his
mother's father (maternal grandfather)
but was disallowed from ever meeting seeing his mother.  
Questions:
does this still happen in the UK?
Can it apply in countries like USA and Canada?
What was the reasoning behind this type of settlement?

Cheers
Mongolia