It was only the prosecutor, not the judge or jury. The issue is that the Post Office lied to the judge and jury about their evidence.
There were a (relatively) small number of prosecutions from the CPS as well, which suffered from the same problem: the Post Office investigators gave the same bad evidence, which they used to convince a jury to convict.
I don't see how separation of powers helps here. I'm sure if I looked, I'd find cases in the USA where the police and/or prosecutors told a pack of lies based on dodgy evidence to secure convictions of serious crimes, too.
Prosecuting directly meant there was no outside eyes on a lot of the cases, no questions about if it was actually in the public interest to prosecute, or external assessment of the evidence before pushing for plea deals.
It's not a foolproof system, but I think most of the cases you'd find about 'dodgy evidence' would also mention a 'overly close relationship between police and prosecutors' - because fully independent prosecutors should be rejecting cases with dodgy evidence. The police can get a bit grumpy with CPS for being quite strict at times - but it holds them to work their next case properly.
The PO clearly managed to convince the CPS in a number of cases, but had they had to do that for all there would have been a lot less cases prosecuted in total, and I think there would have been questions about their system a lot sooner.
It might not have avoided the problem, but it would have been much needed additional oversight into what they were doing.
> It's not a foolproof system, but I think most of the cases you'd find about 'dodgy evidence' would also mention a 'overly close relationship between police and prosecutors'
So the separation of powers isn’t a magic solution to the problem then.
In the US the police are specifically allowed to lie to suspects, whereas British cops are not. If you can prove the police lied in a recorded interview or something used in evidence in court that's going to be a big problem for prosecutors in the UK but not in the US where it's expected.
I don’t think they perjured themselves which isn’t the same as saying they didn’t lie. It’s easy to not perjure yourself if you’re not asked the right questions.
The lie came from the fact they weren’t looking into their own evidence and realising something was up when they were prosecuting hundreds of sub-postmasters.
There were a (relatively) small number of prosecutions from the CPS as well, which suffered from the same problem: the Post Office investigators gave the same bad evidence, which they used to convince a jury to convict.
I don't see how separation of powers helps here. I'm sure if I looked, I'd find cases in the USA where the police and/or prosecutors told a pack of lies based on dodgy evidence to secure convictions of serious crimes, too.