Children living in care homes are excessively "criminalised" compared to other boys and girls, campaigners have said.
Research suggests there is a "systemic" problem which leads staff to resort to the police - often in relation to minor incidents that would never come to officers' attention if they occurred in family homes, the Howard League for Penal Reform claimed.
It said police data indicates that some forces have been called thousands of times in the last three years.
In an example outlined to MPs in 2013, officers were said to have been called to a children's home to investigate a broken cup.
Police suggested they were picking up the pieces of a "social care deficit", while there were also said to have been claims that private providers "were using the police cells as respite to cover staff shortages and because staff were not trained and competent to deal with children's behaviour", according to a report published by the Howard League.
The majority of children legally defined as "looked after" are placed in foster care, while others go to secure units, children's homes and hostels. There are around 1,760 children's homes in England.
The study said looked after children in all forms of care are being "criminalised" at a much higher rate than other youngsters.
In 2013/14, 6% of looked after children aged 10 to 17 had been convicted or subject to a final warning or reprimand, compared to around 1% of non-looked after children, it said.
Those in children's homes are much more likely to have been exposed to the criminal justice system than looked after children in other kinds of care, the report added.
The Howard League also requested data from police forces in England and Wales on how often they are called to incidents at children's homes.
The majority of forces for which information was supplied showed an increase between 2012 and 2015, with several recording totals in the thousands.
Some figures will include call-outs for missing or absent children, while others only cover information relating to reports of criminal behaviour.
Howard League chief executive Frances Crook said children taken into care "deserve every chance to flourish".
She said: "Private companies, charities and local authorities that are paid a fortune by the taxpayer should give these children what they need and deserve."
Jonathan Stanley, of the Independent Children's Homes Association, said: "Children's homes are the most scrutinised and accountable service for young people, inspected rigorously twice a year.
"If training and competence were issues this would be raised in inspection. Inspection outcomes have risen yet again, according to latest figures.
"Children's homes are very careful as to the young people who they accept. Meeting their needs is paramount. This is closely looked at in inspection."
Olivia Pinkney and Nick Ephgrave, of the National Police Chiefs' Council, said in a joint statement: "Children are children first and foremost, no matter what their background."
They added: "It is vital that all agencies work together more effectively and more determinedly to get their response right.
"The police should not be called to minor incidents which would otherwise be dealt with in a family environment. If this is not appropriate, officers should consider tools such as restorative justice or community resolutions.
"Every effort should be made to avoid holding young people in police cells overnight."
Children's Commissioner Anne Longfield said: "We know that there are an extremely high number of calls to the police from residential children's homes, with one police force reporting 3,500 calls from its 47 children's homes last year.
"Ensuring that staff are able to work in partnership with the police to positively deal with difficult behaviour will be essential if we are to offer children with particularly challenging behaviour the guidance and support of a parent - in this instance a corporate parent."
A Department for Education spokesman said: "The safety and well-being of children is paramount. The rules are clear that no child living in a children's home should be criminalised for behaviour that would not concern the police if it happened in a family home.
"Children's homes are held to account by Ofsted against tough new standards, but we want to do more - that's why we announced a review on how to improve the quality of residential care led by expert Sir Martin Narey as well as new reforms to radically improve the quality of social work"