The council can then reuse the graves. What the rules are may depend on the origin rules from when the graveyard was opened.
War graves are a different matter as they come under the War Graves Commission. We have a big one here in Harrogate. To me a War grave are sacrosanct.
Start messing around with those and then what happens to those in France etc. there would be hell on.
In Hebburn cemetery I have 5 unmarked graves at least of family and there are an awful lot of those.
The vast majority are probably not visited by the family and they may not even know that they are there.
I know that up in Scotland there can be three or more in one grave known as a lair.
If they are going to reuse an area of a graveyard they would have to remove the remains in a proper manner and inter in a new. Grave.
In Hebburn Cemetery to the North of the Kelly graves there are two section that are almost devoid of gravestones my Morris G G/Pts are in a marked grave there but the tombstone a right mess and overgrown.
I had thought of having it overhauled but the cost would be huge and I’m the only one I think that knows of it location/ existence.
If done properly why not reuse those areas.
I am deliberately ignoring other faiths as beyond me. However our burial rules should stand!
I expect there are existing rules that cover that.
The vast majority of people these day probably have no idea where their ancestors are buried. From about 1956 cremation became the norm. I would not wish to be buried!
Allan C.