This article examines whether the UK Freedom of Information Act 2000 has changed Whitehall. Based on a two-year, ESRC-funded study, it evaluates the impact of FOI on five characteristics of the Whitehall model: the culture of secrecy, ministerial accountability to Parliament, civil service neutrality, the Cabinet system, and effective government. Proponents of FOI hoped that government would be less secretive, more accountable and more effective, critics feared that civil servants would lose their anonymity, and collective Cabinet responsibility would be undermined. Drawing on interviews, media analysis, case law and official documents, the article finds that the impact of FOI is modest at most. It is not powerful enough to do much good or much ill, and the feared ‘chilling effect' on candour and record-keeping has not materialized. Leaks do more damage than FOI disclosures. But ministers remain apprehensive about the effect of FOI on Cabinet records and discussions.