More than £300 million of Scottish Government cash will be invested in improving mental health care over the next five years.

The funding will help implement the 40 measures outlined in the Government's 10-year mental health strategy.

It has been branded a "missed opportunity" by opposition MSPs at Holyrood while mental health campaigners at SAMH claimed it "lacks the ambition and investment that Scotland deserves".

Maureen Watt, Scotland's first dedicated mental health minister, said the new blueprint was "not the end of a process", stressing it is "just the beginning".

She told MSPs mental health services had changed "dramatically" over the last decade but there was an "ambition to go further".

Included in the strategy is work to improve the physical health of people with mental health problems, as those with long-term problems can die 15 to 20 years prematurely.

Ms Watt said: "This is a major health inequality. I cannot accept it."

To tackle this, she said she was "committed to ensuring that services such as screening and smoking cessation are supported to help improve participation rates for those with mental health problems".

New powers over employment programmes being devolved to Scotland will see the Scottish Government support people to find and stay in work as not having a job can be "the biggest inequality that people with mental health problems can face".

A new 10-year strategy for child and adolescent health and wellbeing will be developed, covering both physical and mental health.

Ms Watt also pledged the Government would ensure every child "has access to emotional and mental wellbeing support in school".

She stated: "None of the improvements to mental health services will be realised without having the right staff in the right place.

"We will work to give access to dedicated mental health professionals to all A&Es, all GP practices, every police station custody suite and to our prisons.

"Over the next five years, that will mean increasing additional investment to £35 million for 800 additional mental health workers in those key settings."

Billy Watson, chief executive of SAMH, welcomed the new strategy, describing its publication as "long overdue".

While he said the charity was pleased some of its recommendations had been accepted, he added: "We are disappointed it lacks the ambition and investment that Scotland deserves, especially for children and young people.

"We need to make mental health a priority across all government departments if Scotland is to be bold and innovative once again."

Labour inequalities spokeswoman Monica Lennon said: "This long-delayed strategy is nowhere near the scale of ambition we need for improving mental health outcomes in Scotland."

She insisted children and young people "should have been at the heart of this ten-year mental health strategy, not an afterthought".

Ms Lennon stated: "It's disappointing that the SNP government has ignored Scottish Labour's plan for investment in school-based counselling and wraparound early intervention support in schools - because we know that half of all mental health problems begin before the age of fifteen."

Conservative mental health spokesman Miles Briggs said: "This mental health strategy simply doesn't live up to the promises the First Minister has made on rights, resources and reforms.

"The mental health strategy is a missed opportunity and is simply not good enough to deliver a new approach to mental health in Scotland. SNP ministers need to think again."

Liberal Democrat health spokesman Alex Cole-Hamilton said the strategy had been produced "more than 450 days late", adding that over that time waiting times for help had worsened.

He welcomed plans to put specialist mental health workers in GPs surgeries, police stations, hospital A&E departments and prisons, but said: "How will 800 staff cover all these locations when there are more than 900 GP surgeries alone?

"The SNP haven't matched their rhetoric with funding here and elsewhere in the strategy."

A statement from a host of children's charities, including Barnardo's, NSPCC Scotland, Children 1st and Aberlour, said they were disappointed with a lack of detail in the plans.

A spokeswoman for the organisations said: "Whilst there is more of a focus on the role of schools and early intervention there is a distinct lack of detail in the document about what actions will take place to tackle the growing problem of poor mental health in our children and young people.

"We are concerned that there is a lack of clear time-scales for change and no detail on who is accountable should there be no progress on improving the mental health of children and young people.

"We need to see national leadership now, to ensure policy commitments are matched by adequate and sophisticated public investment, in people, resources and relationships, to support the delivery of preventative services and to promote positive emotional wellbeing and resilience.

"There is now overwhelming evidence for this approach. The case has been made, now is the time for action."