Some children who run away from foster care in St Helens are not receiving safeguarding interviews to assess whether they have fallen prey to exploitation, new figures show.
The Local Government Association says growing pressures on councils mean it is becoming "increasingly difficult" to make sure vulnerable children are given the support they need.
Councils are legally required to offer a return home interview to children who go missing from foster care once they are back, in which they can discuss the reasons why they ran away.
They are intended to identify problems in their foster placement, and to assess whether they have been exposed to risks such as sexual exploitation while missing.
New figures from Ofsted show foster children in St Helens went missing on 200 occasions during 2018-19.
But only 145 return home interviews were carried out during this time – a rate of around 73%.
The figures have been rounded to the nearest five.
Iryna Pona, policy manager at charity the Children's Society, said: "Return home interviews are really important as they show the child that professionals care.
"They are also a key opportunity for children’s services to understand if the child is at risk, if they are being groomed to go missing, or if they are not happy in their care placement so the right support can then be organised for them."
While some children may refuse to be interviewed, Ms Pona said failure to act on concerns raised in an initial interview could influence a child's decision to have one the next time they go missing.
A parliamentary report on young runaways published earlier this year highlighted children in care's vulnerability to being groomed for sexual and criminal exploitation – a risk that is heightened when they go missing.
It followed a 2016 enquiry which found local authorities were failing to conduct return home interviews properly, share information about risks to children, or develop plans to safeguard them.
Across England, almost 6,400 foster children went missing a total of 27,000 times over the course of 2018-19.
More than half of all missing episodes (56%) did not result in an interview taking place.
Children placed directly with the local authority were more likely to be interviewed than those with private fostering agencies – 50% compared to just 30%.
Local authorities are responsible for ensuring all interviews are offered, however.
The figures also reveal "huge variations" in uptake rates across the country – something the Children's Society described as concerning.
Four local authorities failed to offer a single interview, while eight had a 100% record.
Judith Blake, chair of the LGA's children and young people board, said return home interviews were "imperative" to get children the help they need.
She continued: “Faced with growing pressures, it is becoming increasingly difficult for councils to offer all children the support they deserve.
"High vacancy and turnover rates are also putting pressure on social workers, who are having to manage increasingly high caseloads.
“Councils want to work with the new government to improve retention and to encourage more professionals to work in children’s social care, while investing properly in the services vulnerable children and young people need.”