Video report by Juliet Bremner
David Cameron has said he is "committed" to putting mental healthcare on a par with physical care, as a damning report lays bare the failings of the sector.
The report, released today by an independent taskforce, said the mental health sector has suffered years of neglect and a lack of funding.
It found only 15% of people who need psychological therapy in England get access to care, according to details leaked over the weekend.
It also found suicide rates in England rising after years of decline and that the average waiting time for a child seeking a routine appointment with a mental health practitioner stood at 21 weeks in 2013-14, up from 15 weeks the year before.
Read ITV News Correspondent Richard Pallot on the long road to reform for the UK's mental health services
The report - The Mental Health Five Year Forward View - is the work of an independent taskforce overseen by Paul Farmer, chief executive of the mental health charity Mind.
The report's recommendations, which include integrating physical and mental health care, are backed by the chief executive of NHS England, Simon Stevens.
The planned reform will be funded by an extra £1 billion a year from the NHS by 2020-21.
Luciana Berger, the shadow minister for mental health, welcomed the report, but said the "real challenge" would be seeing the reforms implemented.
"For too long this Tory Government's rhetoric on mental health has not matched the reality on the ground," she said.
"For the thousands of patients who have been left to struggle without the right support, ministers must keep their promises and deliver these vital reforms that are long overdue."
According to the BBC, which cited a data from a Freedom of Information request, budgets for trusts in England fell by 2% from 2013-14 to 2014-15.