Private prosecution: disclosure of evidence and appeal of conviction.

political analyst

In 2021, some former sub-postmasters and sub-postmistresses (SPMs, to abbreviate it for this thread) who were found guilty on the basis of the infamous Horizon computer system, which was run by Fujitsu on the UK Post Office's (PO) behalf, had their convictions quashed on appeal. Their appeals were based on a civil court judgement that was made against the PO.

From following the reporting of the scandal, I'm aware that there is an issue regarding the disclosure of evidence by a private prosecutor (PP) - it seemed that a PP wasn't under as much an obligation to disclose evidence as a public prosecution service (e.g. the CPS in England & Wales) is. Is a PP legally obliged to disclose evidence that would cast reasonable doubt regarding a defendant's alleged criminality?

Furthermore, the now former PO CEO Paula Vennells was questioned by a Westminster committee in 2013 about Horizon. Why would publicly-asked questions about apparent flaws in Horizon not have been enough for the former SPMs to appeal their convictions without waiting for that civil judgement? Would the Court of Appeal not have considered those questions enough to justify questioning the PO about its disclosure of evidence?

PS: this OP is on foot of the drama, "Mr Bates V the Post Office", which was broadcast in the UK on the ITV Network and in the Republic of Ireland on Virgin Media One.

Peregrinus

As a matter of law, the duty to disclose to the defence evidence that "might reasonably be considered capable of undermining the case for the prosecution" applies equally to the DPP or to a private prosecutor.

I think the issue here is that the prosecutors acting on behalf of the Post Office did not, or at least may not, have been aware of this evidence themselves — it may never have reached them either because of a deliberate decision to hold it back, or because other people failed in their duty, or because of a systemic failure.

One of the jobs of the enquiry will be to find out why this evidence was not disclosed, as it should have been. Presumably between the post office staff and their external advisers there are a lot of people desperately arguing that it was Someone Else's Fault.

As to why the defendants did not seek to get their convictions overturned in 2013, getting a conviction overturned on the basis of new evidence is not easy, and "publicly-asked questions about apparent flaws" would fall well short of the standard of evidence required to overturn a conviction.

Possibly a factor here is that about this time the Post Office launched its own mediation scheme to resolve diputes with sub-postmasters over the Horizon system. It wasn't until that scheme broke down, in I think 2015, that a lot of sub-postmasters thought about launching their own legal proceedings against the Post Office.