This is the second in a three-part series examining how the law allowed the Post office scandal to happen and the role now being played by the law and those who work within it in redressing what has been described as the largest miscarriage of justice in legal history. This part considers the powers of the Post Office as a prosecutor, its duties and obligations and why the Court of Appeal judged the convictions obtained by the Post Office to be unsafe.

Read part one here.

The overturning of the criminal prosecutions: 2015 – 2021

From 2015, some of the convicted sub-postmasters (SPMs) began to apply to the Criminal Cases Review Commission (CCRC), an independent body which looks into cases of wrongful convictions and has the power to send them to the Court of Appeal. Since 2020, the CCRC has referred around 70 SPM cases to the Court of Appeal on the basis that each prosecution was an abuse of the court's process. To date, around 83 convictions have been quashed. The reason why the remainder of the cases have not yet been referred or heard is mainly due to a lack of resources both at the CCRC and the Court of Appeal.

What gave the Post Office the power to prosecute?

The majority of criminal prosecutions in England and Wales are brought by the Crown Prosecution Service (CPS), an organisation independent from the police established in 1985 following a number of miscarriages of justice in the 1970s and the 1980s, such as the Guildford Four and the Birmingham Six. However, any individual or organisation has the right to bring a criminal prosecution against any other individual or organisation. According to the Post Office website, Royal Mail solicitors are the earliest known formal investigators and prosecutors in the world, tracing their origins back to 1683. The Post Office continues to act as a private prosecutor, not under any specific power but exercising the general legal right to undertake prosecutions. Its investigators do have powers beyond those of the average private prosecutor including to access the Police National Computer, to undertake financial investigations to bring restraint and confiscation proceedings and to authorise surveillance to investigate crime. Leaving aside the question of the desirability of a single organisation occupying the roles of victim, investigator and prosecutor given the potential for a conflict of interest, there is no question that it should have had rigorous safeguards in place to ensure the highest possible standards of conduct in complying with its duties and responsibilities as a prosecutor. Quite simply, it did not.

The duties of a prosecutor

Every prosecutor is under an obligation to deal with cases justly, to act independently and impartially and to exercise the highest standards of integrity and care. A key duty and vital to any person receiving a fair trial is that of disclosure. Section 3 of the Criminal Procedure and Investigations Act (CPIA) 1996 imposes a duty on a prosecutor to disclose to the defence any material which might reasonably considered capable of undermining the case for the Prosecution or assisting the case for the defence. That duty continues throughout the criminal proceedings and after conviction.

The evidence that has come to light during the civil and criminal court cases, the media investigations and the public inquiry demonstrates beyond doubt that the prosecutors at the Post Office breached their duties in countless ways. The failure to disclose material to the assistance of the defence appears to be not merely inadvertent but a deliberate policy. A heavy-handed approach was taken, with defendants essentially threatened with more serious theft charges if they did not plead guilty to false accounting and make good their losses, despite the Post Office having no evidence of theft. Investigators were forbidden to even consider Horizon as the cause of the shortfalls. Some investigators have described the Post Office as suffering from "institutional blindness" in its approach to investigations and prosecutions.

What is an abuse of process?

The court has the power to stay or stop criminal proceedings on the grounds that to continue with it would be an abuse of the court's process in two types of cases. Firstly, where it would be impossible for a defendant to have a fair trial and secondly, where it offends the court's sense of justice and propriety to try the accused. A stay of a criminal case is an exceptional remedy, and the second category of abuse is very rarely found.

In each appeal, the defendants relied on the findings of Mr Justice Fraser (Fraser J) that (a) there was a significant risk the shortfalls were down to the bugs and errors in the Horizon system, (b) the true position was not disclosed to the defendants and (c) the Post Office did not investigate the shortfalls and the defendants were unable to undertake their own investigations. They argued that the original criminal proceedings against them were an abuse of process on both grounds. They submitted firstly that as the reliability of the Horizon data was essential to the prosecution, it was simply not possible for the SPMs to have a fair trial and secondly, in the light of the findings of Fraser J, it would be an affront to the public conscience to try the defendants.

Proceedings before the Court of Appeal

During the course of the proceedings, the Post Office disclosed further documents which had not previously been seen by the High Court. The "Clarke advice" was a document prepared in July 2013 by barrister Simon Clarke to advise the Post Office about the use of expert evidence as to the reliability of Horizon in the SPM prosecutions. It specifically refers to expert evidence given by an employee of Fujitsu, Gareth Jenkins, that there was nothing wrong with Horizon. Clarke states "unfortunately that was not the case", pointing out that Jenkins had been aware of at least two bugs but had not mentioned them. Clarke advised that Jenkins should not be used as an expert in any future prosecution.

He also said that the Post Office had breached its duty as a prosecutor in not disclosing the material and that those defendants who had been convicted on it now needed to be informed. Not only are the contents of this document deeply concerning, but it is also astonishing that the Post Office needed such basic advice as to its duties as a prosecutor. But that is not the end. In further advice, Clarke records that instructions were given by the Post Office to its employees to shred minutes of conference calls between Clarke and the Post Office and not to minute information so that it would not be disclosable. Further proof, if needed, that the disclosure failures cannot be attributed merely to incompetence.

The Post Office accepted that in most cases the first limb of the abuse of process argument was made out, namely that the defendants could not have a fair trial. However, it refuted the second limb and the contention that it would not be fair to try them.

In relation to the first limb, the Court of Appeal found that a fair trial was not possible in any of the Horizon cases. The whole basis of the prosecution was that there was a shortfall which had been stolen or at best covered up by false accounting. But the only evidence of the shortfall was the Horizon data. The Post Office's failure to discharge its duties prevented the defendants from having a fair trial on the issue of whether the data was reliable.

In relation to limb two, the Court of Appeal pointed out that the Post Office deliberately chose not to comply with its obligations of disclosure, against a background of insisting the SPMs were responsible for making good their losses or lose their livelihoods. Anyone who raised the issue of computer error was dismissed as "jumping on the Horizon bandwagon". The Court of Appeal concluded that those investigating and prosecuting were influenced by what was in the interests of Post Office Limited, rather than by what the law required, and despite knowing the very serious consequences for the SPMs. The Court of Appeal also took issue with the fact that the courts have been directly implicated by the Post Office's failings, with many judges now faced with the knowledge that they unwittingly sentenced a person who did not have a fair trial. It concluded that if the full picture had been known, the public interest in prosecuting allegations of wrongdoing would have been heavily outweighed by the need to maintain public confidence in the criminal justice system. Each of the appellants succeeded on the second limb of the argument.

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