Key Cases on Disclosure and Evidence

The duty of disclosure is one of the most important obligations in the criminal justice system. The prosecution must disclose to the defence any material that is capable of undermining the prosecution case or assisting the defence case. Failures in disclosure have been responsible for numerous miscarriages of justice.

R v H and C [2004] UKHL 3 (House of Lords) set out the principles governing public interest immunity (PII) applications, where the prosecution seeks to withhold material from disclosure on the grounds that its disclosure would damage the public interest (for example, by revealing the identity of an informant). The court held that PII applications must be the exception, not the norm; that the court must scrutinise the material itself; and that material should only be withheld where the public interest in non-disclosure outweighs the defendant's right to a fair trial.

R v Ward [1993] 1 WLR 619 (Court of Appeal) was a landmark case in which Judith Ward's conviction for the M62 coach bombing was quashed. The court found that forensic scientists and the prosecution had failed to disclose material that undermined the reliability of the forensic evidence. The case led to significant reforms in forensic science disclosure and the establishment of the duty on the prosecution to disclose all material that might assist the defence.

R v Allan [2004] EWCA Crim 2236 concerned the failure to disclose the use of a covert human intelligence source (CHIS) who had been placed in a cell with the defendant. The court held that the deployment of the CHIS and the evidence obtained must be disclosed, and that failure to do so rendered the conviction unsafe.

The Criminal Procedure and Investigations Act 1996 (CPIA) provides the statutory framework for disclosure. The prosecution must make initial disclosure of material that might undermine the prosecution case or assist the defence, and the defence must serve a defence statement setting out their case. The Attorney General's Guidelines on Disclosure and the Judicial Protocol on Disclosure further govern the process. Recent reforms following the Liam Allan case (2017, in which disclosure failures led to the near-conviction of an innocent man) have emphasised the need for thorough review of digital material, particularly phone and social media evidence.