Hello all

The last two days of the Horizon trial are today and tomorrow. It began in March and was knocked off course by the Post Office’s attempt to have the judge recused.

There’s been a lot of water under the bridge since then, but in concrete terms, very little seems to have changed.

One thing we do know for certain is that the judge will be staying the course. That has been confirmed by the Court of Appeal. The rest is up the air – we still don’t know whether the first trial’s findings will be reversed by the Court of Appeal and we are still no closer to finding out whether Horizon is “relatively robust” (claimants’ case) or “robust” (Post Office case).

It’s why I’m rather looking forward to today. Patrick Green QC for the claimants will be on his feet summing up his written closing argument and I’m still not quite sure what the claimants’ argument is. Given that neither independent expert was asked to look at the claimants’ branch IT systems to see if anything had gone wrong, the claimants are reduced to saying “Look! Horizon goes wrong! It might have gone wrong in claimants’ branches!” and the Post Office is saying “Look! Horizon rarely goes wrong! The possibility it went wrong in claimants’ branches is vanishingly small!”

Both experts have also agreed Horizon is so vast as to be unknowable, so I can’t help thinking this trial has been a stupefyingly expensive way to not quite look at the problem properly.

Stephen Mason

One thing that has come in for a bit of a pasting Dr Robert Worden’s statistical analysis. Dr Worden is the independent IT expert contracted by the Post Office. His report concludes the likelihood of any bug causing a “lasting” (he inserted that word into his thinking) impact on branch accounts is tiny. Yet on his final day of cross-examination he agreed even by his calculations 500 branches could have been temporarily affected (there are 550-odd claimants).

Stephen Mason, a barrister who specialises in the presentation of electronic evidence in court, has, with a little help from some brainy statistical friends, had a look at the way Dr Worden’s report was presented in court.

Mr Mason is not kind, venturing: “The approach used in the Worden report is completely irrelevant. The relevant statistical measure is the chance that a branch will be wrongly accused of fraud – not how likely it is that an individual submission will go wrong.”

“I find it amazing”, he concludes, “that Dr Worden’s seriously flawed analysis could be viewed as credible evidence in a court of law.

“Looking at the probability that an account submission can fail and saying it is tiny is meaningless on its own. By analogy, it is illogical to say that if there is only a 1 in a million chance of winning a lottery, ergo any person who claims to have won the lottery must be lying.”

If Dr Worden’s report is as irrelevant as Mr Mason suggests, I am sure the judge will notice. Unfortunately we are not going to get any indication on that until his findings appear in the autumn.

When will the ruling appear?

I rather optimistically thought the second trial judgment might arrive in September, but it looks more likely to be October or during the third trial in November.

It also looks as if the third trial is going to be solely about limitation rather than breach. This is quite a major change from what was initially discussed as it means that all that will happen is either a load of claimants will be told they’re time-barred and therefore don’t have a claim or they won’t. We’re still no closer to any individual damages being decided.

Anyhoo – today’s live tweets from Court 26 start at 10.30am. Mr Mason tells me he will be in court, as will many other camp followers of this trial, but sadly not Karl Flinders from Computer Weekly, whose leg injury has got so bad he is going to see a doctor instead. None of us are getting any younger, and whilst there have been some important milestones in this litigation, none of the claimants are any closer to knowing their fate.

Read the live tweets here. The transcript, claimants written closing and full report will be up on www.postofficetrial.com before 9.30pm tonight.

Have a good day.

Nick