Media playback is unsupported on your device Media caption David Cameron: "We've not done enough to end the stigma of mental health"

David Cameron has called for the nation to focus on mental health after a review revealed inadequate, underfunded care, leading to "thousands of tragic and unnecessary deaths".

The report - by a taskforce set up by NHS England - said around three-quarters of people with mental health problems received no help at all.

Ministers agreed more needs to be done, committing £1bn extra a year by 2020.

The government says this will help treat a million more people a year.

The funds are to come out of the £8.4bn the government has promised to the health service during this Parliament and comes on top of extra money already announced for children's services.

Prime Minister David Cameron said: "We should be frank. We have not done enough to end the stigma of mental health.

"We have focused a lot on physical health and we haven't as a country focused enough on mental health."

Mental health 1 in 4 people experience problems each year 75% receive no help £105bn cost to economy

£9.2bn spent by NHS a year

15-20 years shorter life expectancy for those with severe problems Thinkstock

Analysis: Will the plan work?

Mental health care is sometimes called the Cinderella service of the NHS. Over the years it has been neglected, marginalised and under-funded. The taskforce's report acknowledges this.

So will the recommendations have the necessary impact? Ministers and NHS bosses have all said they're fully committed to it.

But similar things were said in 2011 when the coalition launched its mental health strategy. And, as the BBC reported on Sunday, that didn't stop investment being cut.

With money so tight in the NHS, the nagging fear is that despite the promises being made history could still repeat itself.

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Currently £9.2bn a year is spent on the condition - less than a tenth of the NHS budget - despite one in four people experiencing a mental health problem each year.

The result is that an estimated three-quarters of people go without any help, with the taskforce's report acknowledging that services were so bad that lives have been "put on hold or ruined" and "thousands of tragic and unnecessary deaths" have been caused.

The review also said more attention needs to be paid to rising suicide rates.

NHS England believes the strategy will help to ensure that another one million people receive support - whereas at the moment fewer than two million people do so.

Media playback is unsupported on your device Media caption Nicola Mattocks, 18: I wanted to end my life when I was six

It said the investment promised will help pay for:

An extra 600,000 people to get access to talking therapies for conditions such as anxiety, depression and stress

A screening programme to ensure more people with severe mental health problems get help for physical health conditions, such as heart disease and diabetes

Mental health teams to be put into all A&E units - currently only a minority have them

More support for pregnant women and new mothers - around one in five suffers from mental health problems

Nationwide access to community crisis care teams - only half the country has access to them

It said that together these measures would help reduce the demand on specialist inpatient wards in hospitals and therefore help tackle the much-criticised practice of sending people long distances for treatment.

Paul Farmer, the chief executive of the mental health charity Mind, who led the taskforce, said the strategy should act as a "landmark moment" for mental health care, which was currently "very patchy".

"We are saying to the NHS, to government, to industry, to local leaders and to the public that mental health must be a priority for everyone," he said.

While the extra funding was crucial, he added that some stigma around mental illness "still prevails, right the way inside the health service, as it does in society", and this needed to change.

NHS England boss Simon Stevens said he was "fully committed" to implementing the recommendations.

But Royal College of Psychiatrists president Prof Sir Simon Wessely warned it would take "sustained work" to end the "decades of inequality".

And Prof Sheila Hollins, of the British Medical Association, pointed out such promises had been made before.

"Those suffering from mental illness need to see these pledges fulfilled."

Meanwhile the Welsh government said spending on mental health had been ring-fenced since 2008, with investment topping £600m this year.

The current annual allocation to mental health in Northern Ireland is £247m.

The Scottish government said it had made a commitment to invest an additional £150 million over a five year period in improving access to mental health services.

Explained: What is mental health and where can I go for help?

Mood assessment: Could I be depressed?

In The Mind: BBC News special report (or follow "Mental health" tag in the BBC News app)