The Urban Big Data Centre aims to promote innovative research methods and the use of big data to improve social, economic and environmental well-being in cities. Traditionally, quantitative urban analysis relied on data designed for research purposes: Census and social surveys, in particular. Their qualities are well understood and the skills needed for extracting knowledge from them widely shared by social researchers. With the arrival of the digital age, we produce an ever increasing volume of data as we go about our daily lives from physical sensors, business and public administrative systems, or social media platforms, for example. These data have the potential to provide valuable insights into urban life but there are many more challenges in extracting useful knowledge from them. Some are technical, arising from the volume and variety of data, and its less structured nature. Some are legal and ethical, concerning data ownership rights and individual privacy rights. Above all, there are important social science issues in the use of big data. We need to shape the questions we ask of these data with an informed perspective on urban problems and contexts, and not have data drive the research. There is a need to ask questions about the data themselves and how they affect the resulting representations of urban life. And there is a need to examine the ways in which these data are taken up by policy makers and used in decision making. UBDC is a research centre which brings together an outstanding multi-disciplinary team to address these complex and varied challenges. We are a unique combination of four capacities: social scientists with expertise from a range of disciplinary backgrounds relevant to urban studies; data scientists with expertise in programming, data management, information retrieval and spatial information systems, as well as in legal issues around big data use; a data infrastructure comprising a substantial data collection and secure data management and analysis systems; and an academic group with strong connections to policy, industry and civil society organisations developed over the course of phase one and wider work. In the second phase, our objectives are to maximise the social and economic benefits of activities from phase one. We will do this in particular through partnerships with industrial and government stakeholders, working together to produce analyses which meet their needs as well as having wider application. We will continue to publish world-leading scientific papers across a range of disciplines. We will work to enhance data collections and develop new methods of analysis. We will conduct research to understand the quality of these new data, how well they represent or misrepresent particular aspects of life, and how they are and could be used by policy makers in practice. Lastly, we will build capacity for researchers and others to work with this kind of data in future. Our work programme comprises four thematic work packages. One focuses on understanding the sustainability, equity and efficiency of urban transport systems and on evaluating the impacts on these of infrastructure investments. There is a particular focus on public transport accessibility as well as active travel and hence health outcomes. The second examines the changing residential structure of cities or patterns of spatial segregation, and their consequences for social equity, with a particular focus on the re-growth of private renting. The third studies how urban systems shape skills development and productivity and, in particular, how the combination of home and school environments combine to shape secondary educational attainment. The fourth explores how big data are being taken up by policy makers. It asks what the barriers are to more effective use of these data but also whether they distort the picture of needs which a public body may form.