I am grateful to the journalist Tom Webb, who specialises in data protection, for alerting me to an amendment to the Data (Use and Access) Bill, currently going through the House of Lords.
It concerns the legal presumption that “mechanical instruments” (which seems to be taken to include computer networks) are working properly if they look to the user like they’re working properly. This has come in for quite a kicking in recent years. I was first alerted to it in 2013 by the barrister Stephen Mason.
Mason has spent longer than a decade telling anyone who will listen it is a deeply flawed legal presumption. Here he sets out his reasoning. Mason has won some influential supporters along the way, including Lord (James) Arbuthnot who has also spent longer than a decade campaigning on behalf of Subpostmasters affected by the Post Office scandal.
Although the “mechanical instruments” presumption has never, to the best of my knowledge, been quoted in any civil or criminal proceedings involving a Subpostmaster, it has been said to effectively reverse the burden of proof on anyone who might be convicted using digital evidence.
The logic being if the courts are going to assume a computer was working fine at the time an offence allegedly occurred because it looked like it was working fine, it is then down to the defendant to prove that it was not working fine. This can be extremely difficult to do (per the Seema Misra/Lee Castleton cases).
UK Post Office Scandal:
Seema Misra:
Seema Misra ran a post office in West Byfleet in Surrey and was prosecuted by the Post Office when her Horizon accounts showed a false shortfall of over £70,000.[126] She was convicted of theft and sent to prison when pregnant.[127] A few days before Misra’s trial began in October 2010, three Post Office solicitors, Rob Wilson, Jarnail Singh and Juliet McFarlane, had been told about a bug in Horizon but had not disclosed the information to Misra’s defence team. The solicitors have been reported to the Solicitors Regulation Authority.[128] It was part of a much larger failure of disclosure on the part of the Post Office, a failure that cost Misra a fair trial. Giving evidence at the Horizon IT Inquiry, Warwick Tatford, the barrister who had represented the Post Office at Misra’s trial, acknowledged the failures of disclosure and said that he was ashamed to have been part of the case. He also acknowledged failures in how Fujitsu engineer Gareth Jenkins, currently under investigation by the Metropolitan Police for possible perjury, was instructed as an expert witness.[129] Misra, recalling the moment when she was sentenced to 15 months in prison in 2010, said, “It’s hard to say but I think that if I had not been pregnant, I would have killed myself.” Post Office solicitor Singh meanwhile sent a celebratory email to Post Office managers, in which he said: “it is to be hoped the case will set a marker to dissuade other defendants from jumping on the Horizon-bashing bandwagon”.[130]
Lee Castleton:
In spite of the outcome in the Wolstenholme case, the Post Office continued to pursue subpostmasters in the civil courts. Lee Castleton, a subpostmaster in Bridlington, Yorkshire, was pursued for £25,859 after he refused to pay a shortfall that had been caused by Horizon. The case was heard before judge Richard Havery in December 2006 and January 2007. Castleton represented himself and counterclaimed damages in the sum of £11,250 on the ground that the Post Office wrongfully determined (that is, terminated) his contract as a subpostmaster following his suspension. The judge found for the Post Office on both the claim and the counterclaim.[15] Unable to afford the losses and the £321,000 in legal costs, Castleton declared himself bankrupt.[16] In September 2023, solicitor Stephen Dilley, who had represented the Post Office in the case, told the Post Office Horizon IT Inquiry that the Post Office had known Castleton would not be able to pay if he lost, but wanted to send “a message that they were willing to defend the Fujitsu Horizon”.[17] Dilley defended the decision not to disclose details of the 12,000–15,000 calls being made every month by other sub-postmasters reporting technical problems with Horizon, saying the request for disclosure by Castleton was ‘onerous’.[18]
Richard Morgan, who had designed the strategy of the Post Office case against Castleton and represented the Post Office at trial, denied that he had been given instruction to establish a legal point. He said “he would have told Post Office he would not do it if those instructions had been given.”[19] This strategy was repeatedly referred to as a “nice legal point” by counsel to the Horizon Inquiry, Jason Beer.[20] Richard Moorhead maintains “The same strategy formed a central part of the Post Office’s thinking in subsequent cases and provided a legal rationale for insulating Horizon from legal challenges without proper evidence of its robustness.”[21] The Castleton case was analysed and assessed by the University of Exeter School of Law in 2024.[22]