Improvement of educational attainment in schools in urban, disadvantaged areas is an important priority for policy – particularly in countries like England which have a long tail at the bottom of the educational distribution and where there is much concern about low social mobility. An anomaly in the spatial dimension of school funding policy in England allows us to examine the effect of increasing school expenditure for schools in urban areas. This anomaly arises because an ‘area cost adjustment’ is made in how central government allocates funds to Local Authorities (school districts) whereas, in reality, teachers are drawn from the same labour market and are paid according to national pay scales. This is one of the features that give rise to neighbouring schools on either side of a Local Authority boundary being allocated very different resources, even if they have very similar characteristics. We find that these funding disparities give rise to sizeable differences in pupil attainment in national tests at the end of primary school. This finding lends adds to the evidence that school resources have an important role to play in improving educational attainment and has direct policy implications for the current ‘pupil premium’ policy in England.