At least 5,000 children currently in care have been split from their siblings, a Freedom of Information request to councils in England and Wales has found. Two sisters tell the BBC's Victoria Derbyshire programme what it was like to be separated from as young as nine.
Vicky Willis still clearly remembers the day she was split up from her sister.
"I just remember packing everything and getting in the car. We cried. There was no going back," she says.
"I found it unfair because we hadn't done anything wrong to get separated. We just got taken away and that was that."
Vicky, now 19, was four when she and her two siblings went into care due to neglect.
Five years later, she was split from her older sister Pip, to whom she was particularly close. She was found a placement near her brother, in their childhood town, but Pip moved away to Oxford.
She says she really struggled without having her sister to look after her.
Vicky, who now lives in a mother and baby unit with her two-year-old son, Louie, says she was very jealous of her sister, who was making a new life without her.
"Her accent changed. She became posh. She changed. I didn't change - but she had moved to a new area and a new family," she said.
Loss and bereavement
There are currently more than 70,000 children in care in England and Wales - and many of them, like Vicky, have been split from siblings.
When a court makes a care order for a child or sibling group to go into care, the local authority then becomes responsible for them.
Nearly 2,500 sibling groups, at least 5,000 children, are currently split up in care, data from 50 councils in England and Wales that responded to a Freedom of Information request showed.
In 30 of the 50 councils, more than 50% of sibling groups had been split.
In Islington, 73% of their sibling groups are split up, in Oxfordshire it's 68% and 60% of sibling groups are split in Cheshire West and Chester. And in Bridgend in Wales, 58% are split up.
The Family Rights Group has campaigned for more children in care to be kept together with their siblings.
Its chief executive, Cathy Ashley, said when siblings who had experienced the same things and supported each other were split up, "that sense of loss and bereavement alongside the other trauma can be overwhelming".
"Practically, local authorities struggle to find carers who will take on a sibling group," she said. "It's a lack of importance perhaps being placed on that sibling relationship, but the price of that is being paid by those individual children."
She explained there were times when it was in a child's best interest to be moved away from their sibling group, for example if they needed counselling separately after trauma, but that was not the norm.
"The norm should be that priority is given to brothers and sisters being able to live together like most brothers and sisters," she said.
David Simmonds, Conservative leader of the Local Government Association, said councils consider keeping siblings together as a priority.
"There's a £2bn funding gap in children's social care in England and inevitably that's going to have an impact on the way councils do their work," he said.
He also called on the Children's Minister, Nadhim Zahawi, to listen to the voice of young people in care.
The Department for Education said "local authorities have more than £200 billion available for local services up to 2019-20 - which includes funding for children's services".
Pip, the elder sister, says she loved the family she was taken in by, but would have preferred to be with a different family if the siblings could have been kept together.
Her foster family planned to look after just one child, so it wasn't possible for Vicky to move in as well.
Pip says of her younger sister: "We just had a bond and we stuck together. We had each other's backs. We didn't have a good social worker at the time so we had to rely on each other.
"Being moved from a little village to a big city. I was a three-hour drive away from Vicky. I shut off from everything. Social services set up weekends. It wasn't the same.
"Having your sister there and then the next minute she's gone, is difficult."
Pip says that although it is difficult for foster parents, children should be kept together.
"The damage and cost of sibling separation is way greater than the pressure on a foster parent to raise a sibling group," she says.
Watch the BBC's Victoria Derbyshire programme on weekdays between 09:00 and 11:00 on BBC Two and the BBC News channel.