The disclosure to the defence of material which does not form part of the prosecution case. For criminal proceedings issued after 1 April 1997, the Criminal Procedure and Investigations Act 1996 (as amended by the Criminal Justice Act 2003) sets out detailed rules on the disclosure to the defence of material (‘unused material’) which does not form a part of the prosecution case, and, in cases tried on indictment, requires the defence to serve a statement setting out the nature of the accused's defence, including any particular defences on which he intends to rely and indicating the matters of fact on which he takes issue with the prosecution. In cases tried summarily, the defendant may make a defence statement. As originally enacted, the test for disclosure of unused material was a subjective one: the prosecution was required to disclose any material which ‘in the prosecutor's opinion’ might undermine the prosecution case or assist that of the accused. The test was modified by the Criminal Justice Act 2003 to require the prosecutor to disclose material that ‘might reasonably be considered capable of undermining the case for the prosecution against the accused, or of assisting the case for the accused’. See also criminal procedure and investigations act 1996; defence statement; public interest immunity.
Police officers and others who are charged with the duty of conducting an investigation as defined in the Act are required to have regard to the 1996 Act; the Code of Practice issued pursuant to s 23(1) of the Act (reproduced at Appendix 3); the Attorney‐General's Guidelines on Disclosure (reproduced at Appendix 4) and, in matters to be tried on indictment, the Protocol for the Control and Management of Unused Material In The Crown Court (reproduced at Appendix 5).
In criminal proceedings, an expert instructed by the prosecution is required to comply with the disclosure provisions of the 1996 Act. The Attorney‐General has issued a booklet entitled ‘Disclosure: Expert's Evidence and Unused Material‐ Guidance Booklet for Experts’, designed to provide a practical guide to disclosure for such witnesses, reproduced at Annex K to the CPS Disclosure Manual (see <http://www.cps.gov.uk/legal/section20/chapter_a_annex_k.html>). See also expert evidence.