NHS managers could be forgiven for asking why they should be interested in the government’s long-awaited Green Paper on adult social care. The prospect of swine flu, shifting political priorities and impending fiscal gloom might seem enough to worry about.

It is because the NHS cannot respond to these challenges effectively without a radically reformed social care system that the Green Paper should be near the top of in-trays across the health service.  If organisational self-interest was all that mattered, then there at least three reasons why the NHS should take this Green Paper seriously.

The first is that without a properly funded social care system more people will end up in the most expensive part of the NHS – acute hospitals – through emergency and avoidable admissions. And more will struggle to leave it - delayed transfers of care. Evidence is growing of the value of social care investment in keeping people out of hospital through prevention, reablement and intermediate care. Spending on good social care keeps NHS costs down.

The second is that the other big challenge facing the NHS, namely managing the rising tide of chronic disease, cannot be done without information and advice, home care and support for carers. Helping people to live as independently as possible is the natural terrain of modern social care and no credible strategy for managing long-term conditions will work without it. Assistive technology and personal budgets generate new creative possibilities for choice and control. This underlines the need for reform to delivery as well as to funding.

The third reason is longer range but no less germane to the current challenges facing the NHS. Keeping people healthier and well for longer – especially older people – is a major public health challenge where social care, through the role of local directors of adult social services, offers a unique gateway into the wider spectrum of local government-led services like education, leisure and housing. Without a well-funded social care system the local architecture of public heath and partnerships is weakened, along with the capacity to respond to flu pandemics and civil emergencies.

As the arithmetic of public funding swings from addition to subtraction, the consequences of continuing the current two-speed funding regime will add to the misery of both the NHS and social care as they each try to deal with these pressures. The need for radical reform of social care funding is vital not just for the interests of the 1.8 million people who use social care services but also to everyone who uses health services. The NHS now has a real opportunity to show leadership and vision by adding its own powerful voice to the many others that will be heard in the consultation period and beyond. We are all in this together.

Richard Humphries is senior fellow at The King’s Fund.