No, not if it is a legally drawn up will. In this country we do not have strict inheritance rules like the French that lay down stated amounts to go to those in stated relationships.
I think the only reasons for challenging a will in the UK are 'undue influence', where someone persuades someone frail and/or mentally incapacitated to make a will in their favour. These come up frequently. Then if someone is left out of the will who was financially dependent on the deceased, say a child or someone disabled and where someone has worked in a business for a little or no salary because they were cosntantly being told the business would be theirs when a parent(almost invariably) dies.
Gillybob is not wrong, but I think in her MiL's case the money was left to all the children then one died and no change was made to the will. In that case the deceased child's share will go to their children. I inherited a small sum of money from an uncle. It had been left to my father, but my father predceased him, so my sister and I got it.