This in an interesting story, and I wonder how much of it is really the full truth. I grew up in the United States, and my parents took in foster children for many years (my younger sister was adopted through foster care.) My experience with the United States family and children's services programs are that the birth parents are always given far more rights than the children, and certainly more than prospective adoptive parents. We had many children in our home who had required visitations with their families---some supervised and short, some overnight and weekends unsupervised--and in many of these cases the abuse persisted, sometimes got worse, and in one case, the mother consistently used the hour-long visitation to tell her daughter how much she hated her and wished she was never born. But the ultimate goal was always reunification with the birth parents, despite persistent abuse, failure to attend parenting classes, etc.
It's a horrible situation whenever a child is separated from its birth family, but there are truly situations where parents do not love or want their own children.
I'm not familiar with the British system but this story makes it seem that they are far less tolerant of any abuse and move more quickly to get children into an adoptive situation rather than focusing on reunification...