We are in the midst of a very urgent, real, global and deadly crisis. But as that crisis hopefully comes slowly under control, some at least will need to attend to a very different kind of crisis, and one which is scarcely visible. This ‘imaginary crisis’ is the result of a deficit of social imagination. We find it easy to imagine apocalypse and disaster; or to imagine new generations of technology. But we find it much harder than in the past to imagine a better society a generation or more into the future. There are many possible reasons for this decline; loss of confidence in progress and grand narratives; declining imaginative capacity; slowing down of innovation. Key institutions – universities, political parties and thinktanks – have for different reasons vacated this space. The decline of imagination matters because societies need a wide range of ideas and options to help them adjust, particularly to big challenges like climate change and ageing. Social imagination has a long and fascinating history, from utopias to political programmes, model communities to generative ideas and fictions which fuelled our ability to understand and then shape human progress.