Home for Good has been speaking with Premier as new statistics claim two-thirds of local authorities do not have enough independent visitors who can offer friendship and help with making life decision.
Speaking on Premier Christian Radio, Home for Good's Chief Executive Phil Green said: "I'm sure that many of them realise just how important independent mentors are but they operate in a climate when budget are often - or always - being slashed at the moment.
"Good ideas need to be backed-up with resources. I'm sure this morning when many local authorities heard this news, they may have felt a little bit like their hands were tied behind their backs."
Barnardos and the National Independent Visitor Development Project (NIVDP) also concluded only three-per-cent of England's children who live in care has accessed an independent visitors, despite local authorities being legally bond to offer the service to every child who needs it.
Chairman of the Local Government Association's Children and Young People Board, Cllr Roy Perry said: "Although the vast majority of councils currently provide independent visitors to children in their care, there is an urgent need for more volunteers to take on this hugely rewarding role.
"Children have a wide range of needs, so councils need a large pool of potential volunteers to make sure that children are matched with the most appropriate person. We would encourage anyone interested in finding out more to contact their local council."
Barnardo's and the NIVDP are calling upon the government, local councils and charities to think about supporting new standards surrounding support for children.
Barnardo's chief executive Javed Khan said: "Every single child needs an adult they can trust, who will be there for them and stay by their side no matter what life throws their way.
"I urge Theresa May to ensure mentors are in place for young people who are at risk of dropping out of education, training or employment.
"Children in care already have a right to a mentor, but sadly our research shows they aren't getting the support they need."
A Department for Education spokesperson said: "Independent visitors can make a significant contribution to the well-being of children in care and the law is clear that local authorities must appoint an independent visitor where it's in a child's interest and they want one.
"Not all children in care will need or want an independent visitor but this should be kept under review by the child's social worker and Independent reviewing officer."
Click here to listen to Phil Green from Home for Good speaking with Premier's Hannah Tooley.