[notahacker]

The amounts people were prosecuted over supposedly stealing were in the tens of thousands of pounds (some made up the alleged discrepancy by paying back some of their own salary). Not something likely to radically alter the lifestyle of a small business owner (if they had been stealing they'd probably have spent it on cash payments to staff and family, gambling habits and boring stuff like mortgage repayments and savings)

It's crazy auditors didn't spot discrepancies especially with the high base rate of reported frauds and errors, but if finding the receipts for stolen money was the threshold for prosecution any remotely competent thief would be in the clear

[VBprogrammer]

It's hard to say exactly how much a sub-postmaster makes but from a brief search it seems to be in the range of £30k-£35k. It's not like the kind of money these people had down the back of their couch.

If there is absolutely nothing to corroborate the money going missing, no evidence presented for where or how the money was stolen then there shouldn't be enough to send someone to prison.

[UglyToad]

As the sibling comment says (max reply depth reached) the sub-postmasters in general were just about getting by. Part of why this scandal is so egregious is that these people were often just-about-managing under terms of an incredibly unfair contract with the PO.

The amounts of money involved may be small to business owners in other domains but for SPMs many were almost bankrupted by trying to replace the sums out of their own earnings as you say. This wouldn't have been a rounding error to their lifestyle, it should have been provable to any halfway decent investigator. And if not? Then they get away with it and it's the price we pay not to live in tyranny.