British political culture is wary of intellectualism– not for nothing is ”muddle through” a British aphorism– and its governments are usually wary of big ideas. Yet Prime Minister David Cameron has placed intellectuals at the policy heart of 10 Downing Street, allowing a group of social scientists to apply behavioural insights to the design of public policy. The UK’s Behavioural Insights Team, or ”nudge unit,” is just one example of the inroads behavioural sciences are making in governments everywhere. In the following pages, we ask how they are doing.