A lack of time is one of the major reasons given to account for low quality care provided in general practice. One of the basic assumptions inherent in this explanation is that activities in general practice are shaped by the level of patient demand and general practitioners have little control over their work. The objective of this study is to explore empirically this assumption that general practice is demand led by examining the relationship between list size and the time general practitioners spend at work-related activities. The analysis uses data gathered from a survey carried out on a nationally representative sample of unrestricted principals (N = 1419) living in England and Wales. The results show that list size is statistically significantly associated with each of the different indices of time allocation, although it is only relatively strongly associated with hours spent on surgery consultations and surgery consultation rates. The implications of these findings are discussed and it is suggested that the demand led model provides only a partial explanation for variations in time allocation in general practice.