Spatial interaction among local governments in tax setting and public spending decisions is receiving increasing attention in the applied public economics literature. Spatial interaction models rely on the presence of an externality from local budget making: in traditional public finance models, external effects originate either from interjurisdictional resource flows due to tax competition for a mobile base, or from local public expenditure spill-overs into neighbouring jurisdictions. However, the recent political agency/yardstick competition literature has stressed the role of 'informational' externalities between neighbouring jurisdictions, and predicted tax mimicry at the local level. The actual relevance of the above hypotheses clearly needs to be assessed empirically. In this paper, an attempt is made at discriminating between alternative sources of local fiscal interaction, by using data on the English municipal authorities' budgets. While both public spending levels and local property tax rates exhibit considerable positive spatial autocorrelation, maximum likelihood and instrumental variables estimation results suggest that the interdependence among local governments can be attributed to mimicking behaviour in local property tax setting.