Central to the operation of the appellate system, is the ability of individuals who claim that their conviction is in error, to revisit and re-examine evidence gathered during the investigation, as well as that relied upon at their trial. High-profile miscarriages of justice have often only been remedied when there has been defence access to materials post conviction. There is also an imperative for forces to retain evidence in investigations in which no perpetrator has been detected or convicted, to facilitate cold case reviews. In order to give effect then to an appellate system and enable cold case reviews, evidence needs to be retained and properly stored. If materials are not retained and stored correctly, then re-investigations are rendered impossible. Retention is especially critical in respect of physical materials that could be subject to forensic examination. With the progress of science and technology, and the interpretation of results, it is essential that such physical (and now, often digital) materials are retained for future (re)evaluation. From analysis of responses to a Freedom of Information request to all police forces in England and Wales, and qualitative interviews with criminal justice stakeholders, this article examines the retention and storage of materials, and considers the operation and future of the Forensic Archive Ltd. It details a worrying picture of inconsistency, with confusion over what should be retained, and how. It concludes that justice demands that we accept that the proper retention and storage of materials is fundamental to the fair and effective operation of our criminal justice system, and ensures that the Court of Appeal can fulfil its remit in addressing wrongful convictions and forces can pursue justice in cold cases.