A speech at the Oxford Martin School. Richer countries are rapidly ageing and productivity is stagnating. Meanwhile, industry - the motor for rapid economic development in the past - employs ever fewer people worldwide. And yet there is still hope for greater, and shared, global prosperity. Declining working age populations in rich countries are demanding ever-more services. A rising, increasingly educated working age population in lower income economies can provide them. This is an immense, mutually beneficial opportunity to create a new development model, and a new model for development assistance. Aid for economic growth traditionally tried to foster the expansion of export-oriented industrial employment in recipient countries through physical investment. In the future, it can foster the expansion of expatriate employment through skills partnerships.