Last autumn the Observer joined forces with Nesta to find examples of inspirational Britons improving the lives of people and communities across the country in radical and creative ways. Here's how we arrived at the 50 visionary projects

Last November, the National Endowment for Science, Technology and the Arts (Nesta) teamed up with the Observer to launch a call to find 50 of Britain's new radicals. We wanted to find people who were coming up with creative answers to the big issues of our times, working below the radar of national media. We wanted to celebrate people who were really doing good rather than celebrities famous for being famous. And we wanted to find examples of inspiration during a difficult time.

We were bowled over by the response. Many hundreds of nominations came in from every part of country, the great majority of them impressive and intriguing combinations of big vision and practicality. We don't pretend that there was any science to our selections. We tried to strike a rough balance, from business to science, arts to community, with one or two better known projects alongside others that are almost wholly unknown. But we had to exclude many brilliant people and ideas, and the judges didn't always agree.

The bigger message we've taken away is that a similar exercise could be done in every region, and every city. Britain is rich in radicalism, and anyone who says that our society has drifted into fatalism and apathy should get out more.

Not surprisingly, we found some common themes. Many of the nominees – Rubies in the Rubble, Transition towns and the Green house – were involved in reuse and recycling. The extent to which we waste things becomes even more of an affront in times of austerity – and we were impressed by the number of great ideas for making use of otherwise wasted food, buildings or land. Another large group were making the most of digital technologies, smartphones and broadband – from entrepreneurs such as Michael Acton-Smith, to social entrepreneurs (Iris Lapinski) and computer scientists (Open Street Map). Many nominees offered creative responses to the return of mass unemployment – from Women Like Us to Working Rite. The longer-term trends of ageing are also calling forth imaginative responses such as Dementia Adventure and Shared Lives.

It was also heartening to see how many of the professions are trying to instil a stronger sense of mission – like the doctors reinventing themselves as community activists in the Liverpool Project or as patient mobilisers (in PatientsLikeMe), or the lawyers offering their services in i-Probono and Just for Kids Law. There were parallel projects in teaching, architecture, accountancy and journalism, and in the Finance Innovation Lab there's an imaginative effort to find financial ideas that actually create value.

In the list, too, are brilliant inventors – like the inventors of graphene or sugru, and Michael Korn, inventor of a new generation of designs to improve life on hospital wards, as well as public officials from local government to Whitehall.

Hopefully this exercise will prompt argument. If we aren't told of hundreds of people who should have been on the list, we'll be disappointed. If we don't prompt a debate about what it means to be radical, that would be a shame too. For me it means a willingness to deal with the root causes of things, to think and act in genuinely fresh ways. Two centuries after the word first came into use, and at least 150 years since some people started calling themselves new radicals, the word doesn't always mean being novel – many of the best radical ideas involve return as well as advance, like the many projects reimagining Britain as a nation connected to the land and food production. But it does require a willingness to challenge the mainstream.

Thomas Edison famously said genius is 1% inspiration and 99% perspiration and my guess is that persistence will be the single most important factor determining which of the 50 radicals here achieves most in the next decade or two. Being radical guarantees that you'll have to deal with enemies, obstructive vested interests and bitter setbacks. What makes the difference is whether you bounce back – as social activist Michael Young used to put it, treating "no" as a question.

Radicalism is as British as tea and cakes, as much a part of our make-up as monarchy and football. It will never have its own jubilees, palaces or honours system. But it's a tradition that nee ds feeding, and celebrating, and hopefully we've made a start here.

Geoff Mulgan is CEO of Nesta