The Government risks failing to reach its own standards for mental healthcare because of a lack of funding, according to a former coalition minister.
Norman Lamb said the "huge" financial pressures facing the NHS meant that thousands of mental health patients will not receive help pledged by the Tories.
The funding squeeze also threatens vital waiting time targets for people seeking treatment for conditions including bipolar disorder and OCD, he said.
Mr Lamb worked as mental health minister in the coalition government and is now the Liberal Democrat spokesman on health.
Speaking to The Independent, he said his assessment showed "a continuing disadvantage for those who suffer from mental illness with no prospect of it ever changing".
The Government has said it will spend £1 billion more on mental health by 2020, as part of an £8 billion increase in funding for the NHS.
It has also launched a "parity of esteem" to ensure those with mental health needs are given the same priority as physical ailments.
Mr Lamb has called for waiting time targets similar to those placed on cancer patients or emergency care to be applied to mental health services.
New plans include waiting time targets for depression and anxiety disorders, as well as goals for early intervention in psychosis treatment and maximum waiting times for children and young people with eating disorders.
However the Lib Dem said he had been told by senior NHS officials that the money was not available to put them into practice.
He said: "I asked: is this funded? The answer was no," he said. "So essentially it won't happen."
"The rhetoric is good, and I think when [Health Secretary] Jeremy Hunt says he wants to continue to improve mental healthcare, he means it.
"But you can't do it without the money. When the whole of the NHS is under huge financial pressure, it is mental health that misses out."