In her closing statement to the Post Office inquiry this week, Paula Vennells once again added the brutal murder of irony to her list of failings. Or as the former CEO’s lawyer put it: “She has no desire to point the finger at others.” Oh, Paula. Great to hear your pointing finger has finally been decommissioned – but it’s many years and many, many prison sentences too late for that. In fact, as we bid farewell to the Post Office Horizon IT inquiry, to give it its full name, it’s clear that the prime takeout should be: let that not be an end to it. Justice has yet to be served.

It’s quite something to think that this time last year, ITV had not even aired Mr Bates vs the Post Office, the drama that finally galvanised public anger about the most widespread miscarriage of justice in British history, and led to immediate action from various classes of powerful people who could have done something before, but didn’t. As the year ends, it is possible to say that Mr Bates is now by far and away the most watched drama of 2024 – in fact, the most watched anything bar sport. Pretty sensational for something created so faultlessly and beautifully out of a dauntingly unpromising dramatic premise: a faulty computer system.

I wonder what the total sum of money is that the 900-plus wrongly accused post office operators were accused of stealing from the Post Office? Whatever it was, it will be orders of magnitude less than the £130m of taxpayers’ money that the Post Office was yesterday revealed to have spent just on lawyers, just at this inquiry, to defend its indefensible actions. And that figure does not even yet include costs for the current tax year, throughout which the inquiry has run.

Once again, the serious money is flowing in a direction other than towards the victims. Two decades after he first disputed the government-owned Post Office’s assessment of shortfalls in his branch’s account, Alan Bates is still waiting to be paid full and proper compensation by the British state. So are the vast majority of other victims, who remain trapped in bureaucracy that doesn’t feel a million miles from the corporate psychopathy that drove them into ruin and/or imprisonment in the first place. Only around one in 10 of the wrongly convicted post office operators have agreed a final settlement. Not, of course, the ones who died or took their own lives as this story continued its dogged and mostly doomed-looking march. Bates now says they may yet be forced to go back to court.

One of the most hammy pieces of evidence put before the inquiry was a text message to Vennells from former Royal Mail CEO Moya Greene. “I think you knew,” wrote Moya to Paula. “How could you not have known?... I can’t support you now after what I have learned.” We must wait for inquiry chair Sir Wyn Williams’ verdict on who knew what. But the broad-brush answer is: plenty of people. And they didn’t just know – they were the ones doing it. Telescoping all the anger on Vennells would be a very convenient mistake. There was a whole level of executives and other employees at the Post Office, at Fujitsu, and beyond, who should and must have known – and in some cases, demonstrably did.

But then, the absolutely crucial thing to grasp about the Post Office scandal is that there are two classes of people in this story – the sort of little people who go to prison, and the sort of big people who wrongly send them there, yet fail upwards thereafter. Post the Post Office, if you will, Vennells ascended to other boards, the new year honours list, the Cabinet Office. You have to think it is honestly easier to leave the yakuza than it is to be cast out of the upper tiers of business in this country. Earlier this year it was revealed that Paula – who famously moonlighted as an Anglican priest – had been the now-outgoing archbishop of Canterbury’s pick for bishop of London, despite having never held any serious position whatsoever in the Church of England. Many of her senior colleagues also moved on to bigger, better, even more lucrative things.

And yet, not to get the old moral weighing scales out, but wrongly jailing innocent people is so much worse than stealing a few grand, isn’t it? Which the post office operators obviously didn’t even do. The executive class in this story did something truly abhorrent – yet for them, no charges have been brought.

Will they be, once Sir Wyn has delivered his report? They certainly should be. I don’t think it is an exaggeration to state that the health of our dangerously unwell society depends on this kind of justice being served. The repeated failure to bring big people to justice for ruining little people’s lives – and the unexpected shockwaves that flow from those failures – may turn out to be the defining story of the first half of the 21st century.

Every year brings new examples, whose ripple effects we can’t specifically calculate, but which, in the name of sanity, we should surely have got at least a clue about now. The failure to hold anyone at all responsible for the financial crisis of 2008 quite understandably fuelled populist politics that has led to some of the biggest shocks and upsets of the past decade. The notion of “one rule for them” has taken various forms, with “two-tier” currently the buzzphrase of choice. But lots of things ARE two-tier. The Post Office scandal most certainly will be another one of them, unless a proper parade of executives find themselves in court like their hapless underlings once did – only on rather stronger evidence.

• Marina Hyde is a Guardian columnist