David leads client work at Harthill Consulting, which he co-founded in 1985. With ‘inquiry’ at the heart of his work Harthill engages with global and national organisations to develop wise and capable leadership. Current and recent projects include Transformational Leadership programmes, senior talent career and development workshops, strategic leadership for senior medics and organisational transformation in the oil and gas sector, and developing leadership capability frameworks with a 'constructivist' perspective. He is highly regarded for his contribution in developing Harthill’s Leadership Development Framework (LDF) - an insightful lens for understanding the effectiveness and development of leaders and organisations. David, with the team at Harthill, have developed the Leadership Development Profile (LDP), an instrument for assessing 'constructivist development' in leaders. He has trained and authorised over 700 development professionals to use the LDP through which more than 12,500 leaders worldwide have been profiled. David has co-authored several books including Personal and Organisational Transformations and has co-written the award winning Seven Transformations of Leadership article for Harvard Business Review, which is included in HBR's 10 Must Reads On Leadership. David presented the annual Lilly Lecture on leadership in London 2017 at the Royal College of Physicians and at the Education and Training Foundation in 2014 .