'Foster children harmed by frequent moves'
Vulnerable children are too often shuttled between foster homes, harming them further, says a charity.
Last year, nearly one in four foster children in the UK moved at least once, some six or more times, data obtained by Action for Children suggests.
The charity sent Freedom of Information requests to every UK local authority - and more than two-thirds responded.
Councils said they were doing everything possible to limit the need for children to move around the system.
In the year to March 2015, there were 64,372 children in foster care in the 143 councils that responded to the request.
Most children stayed in the same placement for the year but 14,583 had two or more placements, some 22.7% of foster children: of these 168 had seven or more placements.
|UK Children in foster care|
|Total in foster care||Two placements||Three placements||Four placements||Five placements||Six placements||Seven placements||Total who moved||% who moved|
A shortage of foster carers means it can be hard to find "the right fit" for each child and relationships can break down, the charity explains.
The more frequently it happens, the more damaging it can be for children who have already had tough starts in life, said chief executive Sir Tony Hawkhead.
"Sadly we know that it can be necessary to move children from their current foster homes as relationships between a carer and child can break down, especially for children who have faced the most traumatic experiences and find it hard to trust someone new."
Sir Tony appealed for more would-be foster carers to come forward, "to help children and young people overcome trauma".
Roy Perry, of the Local Government Association, which represents councils in England, said that while the majority of placements worked out, "unfortunately there are occasions when they don't".
Mr Perry, chairman of the association's children and young people board, said the trauma and neglect experienced by many children in the care system could have an impact on their daily lives with foster families.
"Other common factors for having to move a child to a different carer include court decisions, a relationship breakdown between a child's biological family and foster carer, or if the child has severe behavioural problems or health issues that emerge as the child begins to open up about what brought them into care in the first place.
"Whatever the circumstances, councils will do everything possible to limit the need for children to move around the system."
A spokesman for the Convention of Scottish Local Authorities (Cosla) said Scotland's councils were "fully committed to looked-after children and take their duties with regard to them very seriously.
"In all honesty, one of the main difficulties for councils placing children with foster carers is actually recruiting foster carers in the first place."
A spokeswoman for England's Department for Education said the government had put in place "comprehensive and far-reaching support" for children in foster care since 2010.
The spokeswoman also said the government was working closely with councils "to help them recruit foster carers who can meet the needs of children who are harder to place, such as sibling groups and children with complex needs".
She said foster carer recruitment was improving in England while the government also wanted a broader range of foster carers to come forward to help improve placement stability and permanence.