This week Nesta launched a new prize supported by the Cabinet Office to reward innovations that can reduce isolation amongst older people.

Here we set out some of the background thinking - and why policy initiatives like this week's white paper need to be matched by much more systematic innovation.

For decades now ageing has been talked about as a problem - a time bomb or crisis. And usually - as with today's white paper - it is discussed as a problem of numbers. With life expectancy rising by five hours a day it is obvious that we need to radically change how we pay for care and pensions.

But to see things only through the lens of today's economics misses what in the long-run may be the most important choices, because ageing is not just a question of distribution and funding, it is also a question of innovation.

This means asking bigger questions: how well and how fast we can develop better systems to cope with ageing; how to make the most of the advantages, and disadvantages, of rising life expectancy; and to reduce unnecessary spending.

The current systems of eldercare are broken. Older people say they want to be active and that they want to be surrounded by those they love, particularly at the end of their lives. And yet the ways in which we deliver care, whether in hospitals or care homes, drive in the opposite direction.

There is a real need for innovation. We need fresh thinking that builds relationships, connections and activity amongst older people.

This is why yesterday, amongst other research and projects around ageing, Nesta's Centre for Challenge Prizes launched a challenge prize to reduce isolation and loneliness in old age. There is a prize fund of £50,000, funded by the Cabinet Office, for the idea that most effectively answers the need.

We have launched this initiative because we believe that so much more can be achieved by encouraging people to come together to create new solutions through sharing their time, skills and knowledge.

However, the risk is that the innovation imperative may be overshadowed by the arguments about financing the current models of care.

The result is a great deal of unnecessary suffering and unnecessary cost. Hospitals and other vital local services still face insufficient incentives to reduce admissions, which is why so many older people come in and out of hospital at great expense. They still have insufficient reasons to make it easier for people to die at home. And residential care homes too often act just as containers for older people, rather than enhancing their quality of life.

A lot of spending on care is unavoidable. But creative innovations already in place around the world show just how differently things can be organised. Past innovations like hospices and the University of the Third Age have become part of many peoples' lives.

Many are mobilising unpaid as well as paid carers, volunteers as well as professionals (including projects like Tyze, Care4Care and Shared Lives); many are reshaping housing, to encourage mutual support (like co-housing projects); many are using now ubiquitous technologies - broadband and iPhones - to monitor vital signs and falls more quickly, like the NHS's Whole Systems Demonstrator, the world's largest controlled trial of technologies for care; and many are developing innovations in finance that help the capital rich to buy better services.

Add these all together and it is possible to imagine a radically different system for coping with ageing than what we have today. That system will have a significantly different economic structure to what we have today and will almost certainly render obsolete some of the forecasts now being used.

The labour market shows just how much can change. More than a decade after a UK government first committed itself to reversing the trends to early retirement, and advocated active ageing, there are now more than 900,000 over 65s in jobs and the fastest growing group for self-employment. And of 3,000 high growth start-ups, almost a third were started by people over 50 years old.

One of the most famous studies of ageing ever showed that when older people in a residential home were given plants to look after, they lived longer. The simple insight that older people thrive better when they have a sense of purpose always gets lost in the national policy debates. But it's likely to be part of how we turn ageing from a 'time bomb' into an opportunity.

Politicians need to get to grips with the policy choices around care. But if they don't put equal effort into innovating better systems for care they'll have missed the bigger picture. Any future strategy for medicine, for example, takes for granted that the choices are as much about innovation as they are about today's approaches.

The same is true for social care policy. But whereas huge R&D budgets flow into new medicine, no one is held to account for their success in innovating for a better old age."