Kathryn Greenfield became dissatisfied with her pupils' written responses, particularly the rather limited explanations that they were giving in support of points that they made. Drawing here on recent work in using Virtual Learning Environments (VLEs) to develop pupil historical argument and reasoning, Greenfield explains how she used web debates to help develop the explanations that her pupils offered in response to a number of enquiry questions. In many ways this work was inspired by the Historical Association Centenary Debates, more information about which can be found at www.history.org.uk. (Contains 12 figures.)