Mr Bates vs The Post Office true story: The scandal behind ITV's drama

She added: "We must be able to keep making them, because Mr Bates vs The Post Office shows that drama can help make a difference, and importantly that the audience wants to hear them."

Despite pre-release concerns about the breadth of its appeal, the four-part factual drama has gone on to find a broadcaster in 12 other territories (as of March 2024), including Belgium, Australia, Hong Kong and Ireland.

The more people who know about the grave injustice suffered by Post Office workers, the more urgency there will hopefully be to find an adequate resolution to this heartbreaking saga, which has already stretched across more than two decades.

The UK government has been under pressure to move the case along since Mr Bates vs The Post Office debuted, although campaigner Alan Bates has voiced stern disapproval of the latest compensation offer placed on the table.

The series also drove more than 1 million people to sign a petition demanding that former Post Office boss Paula Vennells hand back her CBE – which she did in January amid the mounting calls.

Read on for more details on the shocking true story that inspired Mr Bates vs The Post Office.

Mr Bates vs The Post Office true story: What went wrong with the Horizon IT system?

Although the case hasn't always attracted much media attention, the Post Office scandal has been gradually unravelling for more than two decades.

In 1999, a Fujitsu-designed computer accounting system named Horizon was rolled out at Post Office branches up and down the country – the result of a £1.5 billion investment intended to make their operations more efficient.

However, it wasn't long before some subpostmasters reported issues with the new method of working, as Horizon repeatedly flagged losses in their accounts, which in some cases ballooned to tens of thousands of pounds.

In several incidents, the Post Office would demand that the individual employees make up the shortfall using their personal finances – a company policy – which left numerous people in a position of financial ruin.

If that wasn't bad enough, criminal prosecutions were brought against more than 700 Post Office workers on charges of theft and false accounting related to the flawed Horizon system.

Mr Bates vs The Post Office co-star Julie Hesmondhalgh said: "The Post Office was actually doing the prosecutions, investigating their own workers, cracking down as they saw it on ordinary people running post offices in the home counties or whatever.

"I thought, 'Nobody would write this – it can only be real life that's so bonkers in that way.'"

Following a tip by sacked subpostmaster Alan Bates, the matter was highlighted in a feature by Computer Weekly published in 2009, marking one of the first major pieces of coverage that the scandal achieved.

In the wake of the article, Bates formally launched a campaign for justice which attracted a diverse group of victims – each of whom was told at one point that they were the only one – and support from the likes of then-Conservative MP (now Lord) James Arbuthnot.

Mounting pressure led to the Post Office launching an external review of Horizon in the summer of 2012 – almost a decade since Bates initially reported an issue with the system.

The company's private prosecutions related to Horizon stopped in 2015, when a House of Commons Select Committee was also launched to investigate complaints into the IT system and the resulting mediation scheme.

It wouldn't be until November 2018 that the subpostmasters would get their day in court against the Post Office, which ultimately reached a settlement with the group of 555 individuals at a cost of £57.75 million.

However, due to enormous legal fees, only around £12 million of that could be shared among the claimants – equating to as little as £20,000 compensation for people who had lost their money, homes, reputation and priceless time.

Following the verdict, the Post Office was ordered to set up the Historical Shortfall Scheme (now Horizon Shortfall Scheme), which would provide compensation to subpostmasters impacted by Horizon faults.

However, those named in Bates's case were not eligible to apply for the scheme, leaving them worse off than their peers – an injustice corrected in March 2022, when the government announced a Group Litigation Order for this cohort.

Alan Bates said: "For me to try and draw a line under my involvement will be when the initial 555, the group that brought the court action, have received the financial redress due to them. That's a process that is underway now, and in theory, should be finished by August of next year.

"You will never be able to repay people for what they've gone through and you will never be able to give them back all those years of suffering that they've had to endure. But hopefully it might alleviate some of their problems going forward.

"Another issue, and my current source of campaigning, is around the mental anguish of the families. At the moment, the government hasn’t taken that on board. These families need professional mental health assessments and support, not just financially but in other ways as well."

Post Office workers have reported being shunned by their local communities when the allegations of theft were made, as well as suffering from depression and PTSD as a consequence.

Who was the CEO of the Post Office during the scandal?

There have been calls for executives involved in the scandal to face repercussions, including Paula Vennells, who was chief executive officer of Post Office Limited during the scandal.

Bates rejected an offer to receive an OBE at the start of 2023 on the grounds that the former Post Office CEO still has her CBE.

The boss became a figure of controversy for her firm defence of the Horizon system over many years, in the face of growing evidence that it wasn't functioning properly.

Bates added: "How can an honours system work when they're allowing people like her to hang on to something awarded for the disaster she oversaw during her tenure?"

Vennells has now said that "it is beyond doubt there are serious and unanswered questions as to the manner in which subpostmasters were wrongly prosecuted" (via MailOnline) and, in 2021, said she was "truly sorry" to 39 former employees whose convictions were quashed (via The Guardian).

However, as of September 2023, only 86 of more than 700 subpostmasters had seen their convictions overturned, with dozens dying in the time it has taken for the public inquiry to be completed (via The Times).

The Post Office scandal is regarded one of the largest miscarriages of justice in UK history.

Does the Post Office still use Horizon?

A different version of the programme is used today, but the Post Office website states that the IT will be replaced with a new cloud-based system in the future.

"There have been several versions of Horizon since its introduction in 1999 and the current version of the system, introduced from 2017, was found in the group litigation to be robust, relative to comparable systems," it wrote. "But we are not complacent about that and are continuing to work, together with our postmasters, to make improvements.

"We will be moving away from Horizon to a new IT cloud-based system that will be more user-friendly and easier to adapt for new products and services. This is currently being developed with the involvement of our postmasters."

Read more:

• What happened to Paula Vennells from Mr Bates vs The Post Office?
• What happened to Alan Bates from Mr Bates vs The Post Office?
• Mr Bates vs The Post Office star on how legal risks impacted script
• What happened to Jo Hamilton from Mr Bates vs The Post Office?

Mr Bates vs The Post Office is streaming on ITVX now. Check out more of our Drama coverage or visit our TV Guide and Streaming Guide to find out what's on.

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