Only one-in-four children and young people currently have access to the mental health treatment and support they need. Behind that headline figure is a lottery of access and quality.

By 2021, one-in-three children and young people should have access to a service. Again, the picture is likely to be mixed. There is a huge treatment gap and the consequences of this can be lifelong.

This is the question that the University of Birmingham’s Mental Health Policy Commission has been working over the past 18 months to answer.

Our conclusion: simply scaling up access to treatment would be a mistake. Chasing the demand would be the wrong strategy. We need to close the prevention gap and address the causes too.

The Commission asked the NHS Benchmarking Network to produce estimates of the workforce implications and costs of scaling specialist child and adolescent mental health services. They concluded that to reach 100 per cent coverage would cost £1.77 billion a year and require an extra 23,800 staff.

There may be scope to improve productivity. Digital channels could play a part too. But without addressing the drivers of demand, any attempt to scale up access to treatment risks missing the target.

In our report, Investing in a Resilient Generation: Keys to a Mentally Prosperous Nation, we set out a call to action to mobilise national and local government, civil society organisations, academia and business in a shared endeavour. We argue that the government should make this a Grand Challenge, funding a major drive to research, develop and deliver solutions to the number one global health issue.

Our understanding of the lifelong impacts of childhood trauma and adverse experiences is deepening. There is already good enough evidence of the practices and programmes that can make a difference.

We identify four building blocks for a mentally prosperous nation: positive family, peer and community relationships; minimise adverse experiences and exclusions; mentally friendly education and employment, and responding early and responding well to first signs of distress. Each building block has a number of promising and well-evidenced interventions and approaches.

Public Health England, who welcomed the Commission report, launched a Prevention Concordat last year setting out the ‘best buys’ for mental health promotion and illness prevention. The Commission argues that government should back them with investment.

Currently, prevention spending has to compete for funding with day-to-day spending. How do we break the cycle and make prevention the new ‘business as usual’?

The Commission argues that the 2019 Government Spending Review should address this. Thirty years ago, the Treasury separated out capital spending from revenue spending to protect it from the day-to-day pressures of balancing budgets and ensure that long-term investment in infrastructure could be sustained. It worked, mostly.

A similar approach to investing in prevention would help. Longer term, reclassifying public expenditure to make visible the consequences of under investment in prevention and early action would increase accountability.

Three-quarters of life-long mental illness has its first signs by the age of 25. By acting early, investing in the evidence-based prevention we can, over time, improve the mental health of a generation.

If you would like a briefing on this topic then please email Elizabeth Kirsch, Public Affairs Officer.