RARELY has a television drama galvanised the collective outrage of the nation like Mr Bates vs The Post Office.

The post office scandal is the most widespread miscarriage of justice in UK legal history and yet it is only now it has captured the public’s attention.

From 1999 to 2015 the Post Office Ltd – a company owned by the public via the UK Government – blamed 3500 sub postmasters for financial losses caused by computer errors in its Horizon software system.

Seven hundred people were wrongly prosecuted and found guilty of fraud and theft including around 100 in Scotland. Some 236 people were sent to prison. Four sub postmasters took their own lives.

We now know that it was the Horizon software system that created false financial deficits and sub postmasters should never have been prosecuted.

In England, almost all cases except three were prosecuted privately by the Post Office’s lawyers; in Scotland all cases were prosecuted by the Crown Office and Procurator Fiscal Service (COPFS), which is subject to devolved powers and accountability.

So far only 93 wrongful convictions have been overturned by the English Court of Appeal; with four convictions overturned by the High Court of Justiciary in Scotland.

The television drama was first screened on New Year’s Day but within the space of a week more than one million people signed a public petition to strip the Post Office’s former chief executive from 2012 to 2019, Paula Vennells, of her CBE.

Last week Ms Vennells agreed to hand back her CBE as an empty gesture that reeked of cynicism.

What’s now emerged is the long-standing awareness that the Horizon system was defective – yet despite that knowledge, people were nevertheless pursued for fantasy debts and criminal prosecutions.

Last week, we heard during First Minister’s Questions that COPFS was aware of the unreliability of the Horizon system from at least January 2013, but continued with Scottish Post Office prosecutions until 2015.

So many questions remain unanswered. Why no radical action from the UK or Scottish governments on this scandal until now? It’s taken 20 years to set up proper compensation payments and overturn all wrongful convictions.

Why were prosecutions continued with if prosecutors were aware that evidence was unsafe?

When did senior staff at the Post Office and Fujitsu first become aware of problems with the Horizon system?

Why did officials pursue people for debts and prosecutions if they knew there was no reliable evidence to do so?

There is an ongoing public inquiry into the Post Office scandal but that should not prevent the City of London Police’s Serious Fraud Office investigate those at the heart of this egregious injustice.

For me the wider importance of this scandal has best been summed up by the television drama’s executive producer, Patrick Spence.

Mr Spence said: “What is clear is that this story is a metaphor for everything that is wrong in this country.

"We feel that the people who govern us and who oversee us, and who are supposed to have our backs, quite often it turns out they are liars and bullies and cheats. And that’s a horrible feeling to have as a society.”

Let’s hope those responsible for this scandal can be held to account before our legal system as soon as possible.