Brambles or Blackberries

I am not sure of the answer to this but a fellow allotment holder has blackberry plants which she planted several years ago.There is fruit on them now but there are a lot of what I would call brambles.Are these the same as blackberries if not how do you tell the difference.To me they look the same.She would like to cut these brambles? down but does not obviously want to cut down the blackberries.

 

Both Rubus fruiticosus can't have one without the other

 

Brambles, imo, usually refers to blackberries in their wild form.

When you cultivate them you call them blackberries