As part of the Future in Mind initiative the government has set aside an extra £1.4bn for clinical commissioning groups (CCGs) over the next four years to improve child and adolescent mental health services (CAMHS), which they are responsible for commissioning.
But an investigation by charity YoungMinds has found that this year half of the CCGs who were able to give the charity comparative financial data for 2016/17 said they had not increased their CAMHS budgets to reflect the additional investment.
The figure was even higher among the CCGs who were able to give comparative data between 2014/15 and 2015/16. Over this period just under two thirds (64 per cent) of CCGs said they had used some or all of the extra money to backfill cuts or spend it on other priorities.
YoungMinds chief executive Sarah Brennan said: "After years of cuts, the government's recent investment in children's mental health services was hugely welcome, and we should now be witnessing significant improvements across the country.
"But the reality is that the situation varies enormously from one area to the next. While some CCGs have made big increases in their spending, it's deeply concerning that so many others are using some of the new money to backfill cuts or to spend on other priorities."
She is also concerned that so few CCGs are tracking their spend on CAMHS. Of the 209 contacted, 199 responded but just 78 were able to give comparative data for the current financial year and just 89 had full comparative data for 2014/15 and 2015/16.
"If they aren't properly tracking how much money they are spending, it is impossible to say whether services are improving," Brennan said.
"Jeremy Hunt has described CAMHS as the single weakest area of NHS provision, so it is vital that all the new money is spent where it was intended - on creating better services with a greater focus on early intervention," she added.
The YoungMinds investigation is the latest research this year to question CCGs commitment to improving local CAMHS.
In August a study by the Education Policy Institute's Mental Health Commission found the vast majority of CCG plans to improve mental health provision for young people were poor.
And in October former health minister Alistair Burt said the government had "battles" with the NHS to ensure money set aside for transforming children's mental health services is not spent on other things.
Speaking at a fringe event at the Tory party conference Burt said that, amid pressure on health budgets, the NHS had been keen to divert money intended for child and adolescent mental health services (CAMHS) to other service areas.
CYP Now is staging a conference, Improving Children's Mental Health, on 20 January.