At the moment the rough estimate to completely settle the claims from the subpostmasters is in the order of £1 billion. That's a vast amount of money and so, unsurprisingly, there have been noises about Fujitsu footing part of the bill. But if Fujitsu has a financial liability, what about Royal Mail? After all, they did most of the prosecutions. Here's the trick, if the government starts talking about that, then I'd expect Royal Mail shareholders to start talking in terms of suing the government for misrepresentation in a prospectus as to the value of a company being floated on the stock market. I think that this could open up the possibility of both civil and criminal legal action.
That is such a huge can of worms, with executives, civil servants, and politicians potentially being in the frame that everyone with power will want to make sure that that can remains very solidly sealed.
I suspect that that was behind a lot of the evidence by Greene putting on a pretence that before separation Post Office had its own Criminal Law department that was separate from the one in Royal Mail.