A study by the Education Policy Institute's Mental Health Commission rated local transformation plans published by clinical commissioning groups on five areas - transparency, involvement of children and young people, level of ambition, early intervention, including links with schools and GPs, and governance.
Of the 121 published plans, only 18 areas (15 per cent) were deemed to have "good" plans. A further 58 plans (48 per cent) were deemed to "require improvement" and 45 plans (37 per cent) "require substantial improvement".
Clinical commissioning groups, which are responsible for commissioning child and adolescent mental health services (CAMHS), were required to produce local transformation plans by the end of last year to outline how they would spend their share of the £1.4bn Future in Mind funding package announced by government to improve children's mental health services by 2020.
Overall, the report found that local transformation plans were particularly weak on involving children and young people, the level of ambition for service reform, and having strong governance to ensure effective implementation.
On average, localities in the East and West Midlands regions performed best, while plans from the South East and the East Midlands performed worst.
The report does state though that local transformation plans "represent a moment in each area's transformation process" and only the information contained in the public plans, rather than internal documents, could be analysed.
"It may be that there is good work going on in some areas which was not covered in detail in their published plans.
"We recognise that the plans capture a snapshot of activity at a local level, and that areas were starting from very different positions. A good plan may misrepresent what is happening locally and an area with a less effective plan may have made extensive progress since the plan was produced."
The report also highlights issues with recruitment and the way improvements are being funded.
A freedom of information request by the Education Policy Institute found that 83 per cent of CAMHS providers that responded stated that they had experienced recruitment difficulties. The same proportion had to advertise posts on multiple occasions to fill roles.
Recruitment challenges had led to an 82 per cent increase in expenditure on temporary staffing in the last two years. In 2015/16 nearly £50m was spent on agency staff by 32 trusts.
The report adds that the £119m in Future in Mind funding allocated to local areas by government in 2016/17 has not been ringfenced, instead being included in their baseline allocation for "specialist services".
"As specialist services sit within a wider network of support, from youth services to local authority funded charities and social care, there is a risk that the overall budget for children and young people's mental health may not increase or may even be reduced due to wider austerity measures," the report states.
Liberal Democrat MP Norman Lamb, who launched Future in Mind in March 2015 when he was a mental health minister in the coalition government, and now chairs the commission, said: "This report highlights worrying risks to the delivery of the government's major strategy on children and young people's mental health. We owe it to our children to make sure that this strategy succeeds.
"It is critically important that the additional funding secured in the Budget last year is delivered and that all parts of the country commit both to spending that money on children's mental health as intended and to implementing the transformation of services as envisaged in Future in Mind so that we focus on preventing ill health and on supporting families."
Emily Frith, director of mental health at the Education Policy Institute, said: "Mental health trusts around the country are struggling to recruit psychiatrists and nurses. Spending on agency staff has risen dramatically to fill the gaps.
"The Department of Health and its arms-length bodies will need a strong focus on recruitment, retention and improving skill mix to ensure that the children and young people's mental health service has the workforce it needs to meet future requirements."