The polycentric Dutch Randstad and South East England, with London at its core, face remarkably similar challenges. These challenges and the potential solutions formed the basis of a collaboration between LSE Cities, PBL Netherlands Environmental Assessment Agency and the Dutch Ministry of Infrastructure and the Environment. The study investigated how regional authorities in the Randstad and South East England can promote access to both jobs and open space for all income groups, how planners should respond to moderate economic growth or even decline and how metropolitan areas can become more viable and sustainable places to live and work.