Historically the assumption was that a machine under question probably doesn't work, so the prosecution must show to a jury that it works or else they haven't met the burden, you're innocent because the machine doesn't work.
This probably feels fine for a while, and then you discover you're repeatedly releasing people who are very obviously crooks who did exactly what they were accused of, but you couldn't prove to the satisfaction of a jury that the machine everybody knows works does in fact work. They need offer no evidence that it doesn't work, that's your problem, they walk free.
So this assumption was reversed. But then you get Horizon. Did you steal £18,284.27 from the Post Office? Don't say "No" because the computer says you did, and unless you can prove why it's faulty, the Post Office can rely on that £18,284.27 because a computer said so and under law the assumption is that it's correct.
Clearly neither of these simple assumptions is adequate. That's a problem.
None of which justifies what was done to these people, that's over and above the technical legal problem of how to deliver a just outcome - nobody at POL or ICL/Fujitsu seems to have cared about a just outcome anyway.
This probably feels fine for a while, and then you discover you're repeatedly releasing people who are very obviously crooks who did exactly what they were accused of, but you couldn't prove to the satisfaction of a jury that the machine everybody knows works does in fact work. They need offer no evidence that it doesn't work, that's your problem, they walk free.
So this assumption was reversed. But then you get Horizon. Did you steal £18,284.27 from the Post Office? Don't say "No" because the computer says you did, and unless you can prove why it's faulty, the Post Office can rely on that £18,284.27 because a computer said so and under law the assumption is that it's correct.
Clearly neither of these simple assumptions is adequate. That's a problem.
None of which justifies what was done to these people, that's over and above the technical legal problem of how to deliver a just outcome - nobody at POL or ICL/Fujitsu seems to have cared about a just outcome anyway.