The case for impact centres on theory advanced in the award-winning book, The New Psychology of Leadership 2010. The book characterizes the dynamics of the social process that make for effective leaders. Leadership is seen as a group relationship and includes ways that leaders and followers interact within a social group. The theory is already having impact, for example it has been used by the advisor to the Polish president. Public engagement includes a TV company developing programmes on leaders and a leadership training course developed from the book’s perspective. The impact in society may develop further since many domains need effective leadership.