A legal presumption that computer data is infallibile may have led to a major scandal in the U.K: the jailing of hundreds of postal workers on false embezzlement claims tied to inaccurate data generated by Horizon, a sprawling point-of-sale system developed for the Post Office by Fujitsu. A bug-filled and blatantly unviable product, Horizon's mistakes were nonetheless not the problem so much as the prosecutions, convictions and endless buck-passing since at all levels of responsibility. And all of this took place in the shadow of a legal presumption that is, finally, on the chopping block.
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.
The "infallible computers" rule was not apparently invoked in Horizon-related cases, but it didn't have to be to have an effect on proceedings. The "computer says no" mentality and its embodiment in law is recognized now as a creation of prosecutorial convenience whose unexpected outcomes are now becoming quite menacing. It came into being, as reportage has it, to prevent speeding drivers from easily challenging the correctness of early radar speed detectors. As these devices were unreliable, the law moved the burden of proof from prosecutors presuming accuracy to defendants claiming inaccuracy. You might even say, in hindsight, that the point of the rule was to conceal the known and expected fallibility of a mechanical system from the courts and that having created such a monstrous rule of evidence it is no wonder that monstrous outcomes resulted.
The proposed amendment:
This amendment overturns the current legal assumption that evidence from computers is always reliable which has contributed to miscarriages of justice including the Horizon Scandal. It enables courts to ask questions of those submitting computer evidence about its reliability.
