Twenty years ago, we watched from university as the Labour party conference enjoyed the difficulties of Mrs Thatcher’s second term, and deluded itself about its own route to power. Our party was obsessed with the icons and betrayals of the past, and lost sight of the future.

This week’s Manchester conference must not become a 1980s moment. Looking to the challenges of the 21st century, we must talk ideas not division… Understanding the world in which we live in order to be capable of changing the future is the task for the second generation of New Labour. If once it was “the economy, stupid”, today we face “economics plus”. We must respond not just to the widely recognised challenges of globalisation but also the equally powerful force of interdependence. That means economics plus communications, plus travel, plus immigration, plus a sense of the new ways people live their lives.

An interdependent world means we live in communities more diverse and exciting than our parents could have predicted. But it also brings new challenges around immigration and security. We have to work harder at creating a culture of shared values which can balance the beliefs of each with the good of all. The countries that succeed in the 21st century will be empowered societies – creative in their application of knowledge, open and meritocratic in their social structures, pluralistic in their systems of power, and globally linked at the level of citizen, city and government.

New Labour has been good at paying teachers and nurses and police more. But we have to do more to make public servants feel like social entrepreneurs with the power to reshape lives…

New Labour has been more successful than any government since 1960 in reducing poverty. But we have to do more to improve life chances…

Finally, New Labour has been good at responding to crises and understanding the public mood. But we need to do more to develop a different sort of politics and government, where citizens become players and not just spectators.

Alexander is transport secretary, Miliband is environment secretary in the Tony Blair government. Excerpted from ‘The Guardian’, September 25