Controlling alcohol availability through local policy: an observational study to evaluate Cumulative Impact Zones in a London borough.

Background Cumulative impact zones (CIZs) are a discretionary policy lever available to local government, used to restrict the availability of alcohol in areas deemed already saturated. Despite little evidence of their effect, over 200 such zones have been introduced. This study explores the impact of three CIZs on the licensing of venues in the London Borough of Southwark. Methods Using 10 years of licensing data, we examined changes in the issuing of licences on the introduction of three CIZs within Southwark, relative to control areas. The number of licence applications made (N = 1110), the number issued, and the proportion objected to, were analysed using negative binomial regression. Results In one area tested, CIZ implementation was associated with 119% more licence applications than control areas (incidence rate ratios (IRR) = 2.19, 95% confidence intervals (CI): 1.29-3.73, P = 0.004) and 133% more licences granted (IRR = 2.33, 95% CI: 1.31-4.16, P = 0.004). No significant effect was found for the other two areas. CIZs were found to have no discernible effect on the relative proportion of licence applications receiving objections. Conclusions CIZs are proposed as a key lever to limit alcohol availability in areas of high outlet density. We found no evidence that CIZ establishment reduced the number of successful applications in Southwark.