Disclosure problems have blighted the criminal justice system for too long, the QC investigating the collapse of a trial following the 1988 murder of Lynette White has said in a long-awaited report.

Barrister Richard Horwell QC's investigation into the 2011 trial R v Mouncher and others was set up in 2015 following consultation between the home secretary and attorney general. Horwell, of 3 Raymond Buildings in London, investigated the collapse of the trial of eight police officers charged with perverting the course of justice for their role in the arrest and prosecution of five men for White's murder in Cardiff.

Three of the five were convicted of murder and later had their convictions quashed by the Court of Appeal. Advances in DNA techniques subsequently identified the real murderer.

Today's report concludes the 2011 trial collapsed 'because of human errors by the police and Crown Prosecution Service rather than a deliberate attempt to cover up any crime', the Home Office announced.

Horwell says the trial was 'beset by problems especially those concerning prosecution disclosure'. Disclosure problems 'have blighted our criminal justice system for too long', he says. Although disclosure guidelines, manuals and policy documents are necessary, 'it is the mindset and experience of those who do disclosure work that is paramount'.

Horwell hopes the original defendants 'will now know in detail what happened and will appreciate that the collapse of the Mouncher trial was due to human failings and not wickedness'.

He also hopes to achieve three further objectives: 'First, that a "strict" interpretation of the law applicable to disclosure and a begrudging or reluctant attitude to disclosure, which most criminal practitioners have experienced far too often, will be consigned to the past and a new spirit of openness, generosity and common sense will prevail. 

'Second, that defence lawyers will respond appropriately and play their part by engaging in the disclosure process and not holding problems back until the trial is about to start or is underway.

'And third, that debate and concern may be stimulated over the issues raised so that lessons might be learnt and that the errors identified will not be repeated.'

Horwell adds: 'Many a cynical, battle weary practitioner will say that the first and second of those further objectives are unattainable and pure fantasy; I hope they are wrong.'

Some of Horwell's recommendations may seem basic or straightforward, the QC suggests. For instance, 'the abiding principle must be "if in doubt disclose" and nothing must be permitted to qualify or diminish it'.

A CPS spokesperson said: 'We have recognised and accepted the shortcomings identified in this case previously but we are pleased Richard Horwell QC recognises the significant improvements we have made in how we disclose material in serious cases. We will study the findings of the report in detail to consider whether any issues have been identified which have not yet been addressed.'