Staff from the creator of the Post Office’s Horizon computer system referred to an expert witness as a ‘git’ and decried sub-postmasters defending themselves as a ‘gaggle’, the public inquiry into the scandal has heard. 

During a fractious and at times tense exchange last week, internal emails were shared with the inquiry showing Post Office was worried about a ‘precedent’ being set if doubts about the Horizon system were made public.

Lawyers for hundreds of victims of false prosecutions accused contract managers of seeking to ‘cover up’ system flaws to ensure people could not use them as part of their defence.

The inquiry heard last week that an in-house solicitor for the Post Office had advised that the organisation ‘throw money’ at silencing a sub-postmistress from Cleveleys in Lancashire who had tried to argue there were defects with the Horizon system which were causing a shortfall at her branch.

The case was one of the earliest of the 700-plus civil and criminal actions brought against Post Office employees falsely accused of theft or fraud over the following decade. Many lost livelihoods, had families torn apart and were shunned by their local communities.

As part of the Post Office’s civil claim against Julie Wolstenholme, a joint IT expert had been instructed to look at the data available and he reported back that the system was defective and that the helpline set up by Post Office was more concerned with closing calls than preventing a reoccurrence of faults.

The inquiry heard that following this report, an internal memo was sent by Post Office contracts manager Keith Baines to his counterpart at IT giant Fujitsu. The document stated that Post Office was ‘concerned by [the expert’s] findings, not only in relation to this particular case, but also because of any precedent that this may set and that may be used by Post Office’s agents to support claims that that Horizon system is causing errors in their branch accounts’.

The inquiry heard that, during the course of the litigation against Wolstenholme, Post Office submitted a statement of truth that ‘any faults that occurred in the Horizon system were eliminated once they were identified’ and that the IT was fully tested and fit for purpose.

The litigation continued, and at one stage Post Office’s external lawyers from Weightman Vizards (now Weightmans) wrote to Wolstenholme saying that she had made a procedural error and threatened to apply for summary judgment. In a letter shown to the tribunal, Wolstenholme responded to say she was ‘quite upset with the attitude’ of Post Office lawyers and to ‘please bear in mind I am just a lay person trying my best to understand legal procedure’.

The inquiry heard that when the IT expert reported on faults in the system, Fujitsu directors' emails suggested ‘another opportunity to influence’ him by inviting him to the company headquarters and see more data and records.

When the expert continued to back his initial opinion, Jan Holmes, former Fujitsu audit manager, emailed his colleague Colin Lenton-Smith saying that ‘if I continue I fear I may call [the expert] a git, or something worse’.

Holmes then wrote a further email entitled ‘risk position on litigation support’, in which he referred not only to Wolstenholme’s case but another case from a Post Office branch in Derbyshire where a postmaster had raised concerns about Horizon.

Holmes had said: ‘Although Cleveleys may appear to be closed it could be construed that [Post Office] bought off Mrs Wolstenholme rather than defend their system. Even if a gagging order is placed on the woman she apparently had a gaggle of postmasters lined up to support her case and they will be well aware of what the final outcome was. I’m sure that they will not be keeping quiet.’

Holmes had asked in this email how many more ‘howlers’ existed and suggested that ‘two out of two is a bit of a worry’.

Christopher Jacobs, instructed by Howe & Co to represent more than 150 victims of the scandal, said Fujitsu staff were ‘complicit in this cover-up’ by seeking to dismiss complaints rather than investigate them.

He said: ‘When one looks at the correspondence we have looked at between Mr Holmes and [Lenton-Smith] it is quite clear that Post Office were seeking to cover up their own expert opinion that showed that Horizon was defective because they didn’t want that to get out to sub-postmasters.’ Lenton-Smith responded that he could not comment on that, but stated there was ‘no evidence’ to say that Fujitsu was not open about its system.

The inquiry has now broken for the summer and will reconvene on 19 September. Among the witnesses due to give evidence in the first week back are Stephen Dilley, solicitor with conduct of the civil proceedings against Lee Castleton, and Mandy Talbot, former Post Office legal case manager.