At least 8,600 new foster families are needed across the UK this year to provide stable, secure and loving homes for record numbers of fostered children, a charity said today.
More families are needed not only to replace the 12% who leave each year, but to ensure that children find carers who are right for them, have the skills and qualities they need, and are available now, said the Fostering Network.
Almost 63,000 children are living with more than 52,500 foster families across the UK, and more families are particularly needed to provide homes for teenagers, children with disabilities and sibling groups, the organisation said.
Without enough families willing and able to offer homes to these groups, some children will find themselves living a long way from family, school and friends, being split up from brothers and sisters, or being placed with a carer who does not have the ideal skills and experience to meet their specific needs, it added.
Research by the charity in 2013 found that in the previous two years one in three foster carers had felt under pressure to take children - usually teenagers - who they were not trained or supported to look after. One in 10 had felt under pressure to take in a child, again usually a teenager, when they felt they had no more capacity. Two in five had looked after children temporarily because the fostering service could not find a suitable long-term home.
In England alone there are more than 4,000 unplanned endings of fostering placements each year and one in three children in care live in two or more homes across the 12 months.
Robert Tapsfield, the charity's chief executive, said: "Children and young people come into care for a wide range of reasons, but all come needing professional, dedicated and compassionate support. Foster carers are remarkable people who open their homes to some of society's most vulnerable and disadvantaged children and young people.
"Fostering services last year found over 7,200 new foster families in England alone, but recruitment remains an ongoing challenge. Fostering services across the UK need to attract a diverse range of foster carers who can meet the needs of children in care and who can offer as much choice as possible so that they can find the right home for each child, first time.
"We urgently need people who believe that they have the right skills and qualities to foster to come forward and make a long lasting positive difference to the life of a child. In particular, foster carers are needed to provide homes for teenagers and children with disabilities, and to help sibling groups stay together."
An additional 7,000 families are needed in England, 200 in Northern Ireland, 850 in Scotland and 550 in Wales during 2014.
The 63,000 children living with foster families make up 78% of the almost 80,000 children in care on any one day in the UK (excluding the minority who live at home with their parents).
Around 30,000 more children come into care over the course of 12 months, with similar numbers leaving the care system to return home, move in with another family member, live with new adoptive families, become subject to a special guardianship or residence order or move on to adult life.
Andrew Webb, president of the Association of Directors of Children's Services (ADCS) said in reaction to publication of the figures: "Foster care is the heart of our care system and, when done well, can change a child's life. At any time, around three quarters of looked-after children are placed with foster carers.
"The number of children coming into care continues to increase, and the reality of their family lives seems ever more complex - so our need for foster carers continues to grow.
"'Care' takes many forms, so we need many different types of carers, with varying skills and abilities, to meet the needs of children. Fostering brings both rewards as a trusted professional colleague and the inherent reward from seeing children thrive.
"ADCS continues to work with the Fostering Network, Government and other partners to ensure that every child and foster family receives appropriate support, and would encourage those who believe they have the right skills to foster to come forward so all of those children who need a foster placement can be matched with one."
The Fostering Network urged people interested in becoming a foster carer to contact their local fostering service. Details of these and more information about fostering are available from couldyoufoster.org.uk.
A Department for Education spokeswoman said: "Foster carers offer vulnerable children the routine and stability they deserve.
"Encouraging progress has been made recruiting more foster carers - a 5% rise in the last year alone. We are making it much easier for people to foster and are spending £750,000 to help councils recruit and retain foster carers to meet the needs of every foster child.
"We have also invested an extra £3.7 million to support vulnerable families and those already fostering. Anyone interested in fostering should call Fosterline - a free, confidential service offering a range of advice and information."