This Practice Note explains the statutory duty on the prosecution of the disclosure of unused evidence in criminal proceedings. It covers when such prosecution disclosure should take place and what unused material should be disclosed. It covers the continuing duty of disclosure and the consequences of a failure to make disclosure of unused evidence. It explains the obligations both on the prosecution and the defence in the context of the statutory regime set out in the Criminal Procedure and Investigations Act 1996 (CPIA 1996) and the Code of Practice under the CPIA 1996 along with the CPS Disclosure Manual, Judicial Protocol on the Disclosure of Unused Material in Criminal cases, and the Attorney General's guidelines on disclosure. It covers criticisms of the disclosure process, the scheduling of unused non-sensitive and sensitive material, handling electronic material and the disclosure review document.