The complainant requested information from the Home Office about a surveillance tower. The Home Office ultimately provided some information and advised that some information was not held. It said that the remaining information was exempt from disclosure, citing sections 31(1)(a), (b) and (e) (Law enforcement) and 21(1) (Information available by other means) of FOIA. The Commissioner has investigated the application of section 31 of FOIA. The Commissioner’s decision is that the Home Office was entitled to rely on section 31 to withhold the related information. The Commissioner requires no steps to be taken as a result of this decision.