In the final two chapters of this book we set out five ways in which jigsaw cities can evolve. In this chapter we look first at the notion of recycling cities through smart growth, and second at the need for neighbourhood management as part of renewing them. In the last chapter we look at what would make cities more sustainable, how to turn existing communities into more mixed communities and how to involve communities more directly in the process.

By thinking of cities as jigsaws that fit tightly together, we see ways of creating sustainable communities within the existing built-up urban frame. There are strong ecological reasons for doing this, as John Reader argues:

To cope with such immense land, housing and social pressures, we need to win people back into cities that are safe, clean and energy efficient, using less than half their current resources. Birmingham and the other big cities outside the South East do not have to be the ‘ugly sisters’; they can spearhead an economic, social and environmental resurgence in the declining regions, where there is so much unwanted, unloved, damaged space, so many wasting assets. Reusing cities limits environmental damage and supports compact, cohesive communities. Nothing less will spare the planet in today's urbanising globe, for nothing less will hold enough people together. Our troubled cities can rival any city in the world with their public spaces and buildings, their undervalued industrial heritage and their social assets as well as their liabilities. The pieces are all there; they need to be made to fit. Birmingham's existing housing and brown spaces could more than meet the city's needs and allow significant growth.