The ITV drama Mr Bates vs the Post Office, on the campaign for justice by former post office operators led by Alan Bates, has caused a national outcry and led to unprecedented government action. From Computer Weekly to MPs, to the specialist forensic accountants brought in to investigate, this is how the story has played out over 20 years.

The journalists

In 2004, Bates approached Computer Weekly’s (CW) investigative journalist Tony Collins over suspicions about the Horizon IT system. It would be another five years before the story saw the light of day. Since then the CW journalist Karl Flinders estimates he has written about 350 articles on the campaign.

But the very first was by Rebecca Thomson in 2009. “Tony Collins could not do anything with one source in 2004. Then in 2008, Lee Castleton came forward,” she said. Castleton had been bankrupted by his legal battle with the Post Office.

Thomson hunted for others. She found Jo Hamilton, forced to plead guilty to false accounting to avoid prison, then four others who were willing to speak. It took nine months to publish, and she had “a really strong sense that this should be significant”.

And then – nothing. “We were hoping for an immediate impact, and that definitely didn’t happen,” she said.

Perhaps it was because “the Post Office was vehement in its defence”, or because it was the operators’ word against the Post Office.” Or, maybe, because “the technical knowledge that Computer Weekly has meant we were more aware, perhaps than other newsrooms might be, that technology is fallible. And there could be something in what these subpostmasters were saying.”

Thomson left CW for a new job in 2010 and Flinders picked up the baton he has doggedly carried ever since.

There was “very little pickup by others” of his scoops. “It’s computers. It’s subpostmasters. It doesn’t sound that interesting. And it was case studies of what people were saying had happened. We didn’t have any hard evidence at that time,” said Flinders.

“But the important thing was it brought subpostmasters together, because the Post Office had been saying ‘you’re the only one having problems’.”

Flinders carried on reporting. “You’d ring the Post Office, they’d always say there are no problems.”

Then in 2013, the forensic accountants Second Sight Investigations, appointed by the Post Office to independently investigate, produced an interim report that contained criticisms.

Flinders was now being contacted by people reading his stories, “saying ‘Look, I’ve had these problems’. But still nobody had hard evidence.”

It was a long, slow journey. But in 2015, he discovered a post office operator who said her computer was freezing when she travelled in remote locations, affecting the registering of transactions. It took him “ages”, but Flinders managed to obtain an internal email talking about this error.

“We thought ‘Wow, that’s a smoking gun’. They have always said there are no errors that can cause losses. But they just replied saying that this didn’t cause any losses.”

It was the 2019 high court group litigation victory of the “555” operators led by Bates against the Post Office that galvanised the story. “It was just amazing, I felt like standing up on the chair and clapping when the judge was reading out his judgment,” said Flinders.

“When I was first writing on this years ago, I always used to tell people, ‘This is going to be massive’. And people would go, ‘OK, it doesn’t sound that interesting’. Now I see the same people and they are like, ‘Wow’.

“I can’t believe it’s taken a dramatisation of a real story to do this. But it really has just done what we have been hoping for 15 years.”

Second Sight Investigations

In his long years of investigating companies, the forensic accountant Ron Warmington, of Second Sight Investigations, said he had “only come across one or two companies managed worse than the Post Office”.

In the ITV drama, Second Sight – called in by the Post Office as MPs asked for scrutiny of the stream of prosecutions – was represented by the character Bob Rutherford. In reality “Bob” is an amalgam of two investigators: Warmington and co-director Ian Henderson.

Paid for by the Post Office, Second Sight agreed to investigate “only if they convinced us that they were going to join forces in a search for the truth, not withhold papers, and let us off the leash to do what we thought appropriate”, said Warmington, the company’s chair.

But as soon as they began to find dubious documents “the cooperation went into reverse”.

While Warmington went out on the road meeting those accused, Henderson was the “documents” man. In some cases it looked likely that the Post Office prosecutions would not have reached the bar for normal criminal prosecution, they believed.

Warmington began to feel “I was in danger of going native”.

“So I said to Ian, ‘I’m starting to sympathise with these people. I’m finding so little, in fact nothing, in defence of the Post Office that I’m running the risk of losing objectivity. So if I come back bleating about the plight of a subpostmaster and blaming the Post Office, I’d like you to attack me and try to demolish my arguments’. And, stoically, Ian did just that. For a good year Ian managed to support that position. But eventually he, too, couldn’t sustain it.”

Second Sight’s interim report in 2013 did not assert that there were any system-wide problems with Horizon. But, he said, they had focused on “spot reviews” that “revealed system flaws and a prosecution process that was all about recovering money rather than identifying the underlying root causes of discrepancies and seeking the truth”.

Second Sight was indicating in 2013 that, normally, companies would consider settling such matters after being notified of such failings.

Instead, Second Sight’s investigative efforts were diverted to the 140 applicants to a mediation scheme. Eventually its contract was terminated, but not before Warmington had contemplated “sacking” his client.

Their final report in 2015 summarised 19 “thematic issues” that they had found across all the cases: “everything from wholly inadequate training, to the likelihood of improper investigation and prosecution practices that were motivated by a desire to recover losses and that proceeded without the supporting evidence that would normally be needed, and a document that contemplated hiding a system bug, and the ways of correcting its impact, from subpostmasters.”

The Post Office issued a report that rubbished Second Sight’s findings. “I was angry until I read to about the fourth page of their 90-odd page rebuttal. Then I started laughing. It was so absurd.

“I thought about responding. But in the end decided to leave both reports in the sunlight and we would see who would be proved right.”

The MP

As MP for North East Hampshire in 2009, James Arbuthnot, now a peer, was contacted by two constituents who told him the circumstances in which both had been sacked by the Post Office. One was Jo Hamilton.

“I believed them,” said Lord Arbuthnot. But as Hamilton pleaded guilty to avoid prison, it was difficult to know what to do.

Then another was removed “for exactly the same reasons”. “That really galvanised me. I thought this cannot be coincidence. There must be something going systemically, seriously wrong.”

He wrote to other MPs. Some were asking “the occasional question” in the House of Commons. “But there was nothing like the groundswell, looking back, that we now see ought to have been happening,” he said.

That began in 2011, by which time there were about 50 cases of which MPs were aware. The MPs were led by Arbuthnot, who continues to champion the campaign.

“The major difficulty has been this business of an arms-length arrangement between the government and the Post Office,” he said. It means the government leaves operational and contractual matters to the Post Office. “The sole shareholder was repudiating all responsibilities of ownership,” he said.

“It’s like having a dangerous dog who bites someone and you say, ‘I’ve got an arms-length relationship with this dangerous dog, nothing to do with me’.”

Arbuthnot added: “I don’t think the arms-length arrangement is sustainable.”

He believes that when the Post Office called in Second Sight Investigations Paula Vennells, the chief executive, and Alice Perkins, the chair, “wanted, and expected, to (a) get to the bottom of it, and (b) having done so to find Horizon was as robust as they thought it was”.

That was not to be the case. Second Sight’s contract was terminated, the Post Office stopped its mediation scheme, and the operators felt they had no option but to go for group litigation, needing to find more than 550 claimants to pursue their case.

“Alan [Bates] was then able to get 555 people – an astonishing thing to achieve to take the most trusted brand in the country to court. How he managed to persuade litigation funders to take on a government-funded organisation like that I cannot imagine. But he did. And the hero of all of this, as we now know, is Alan Bates,” said Arbuthnot.

Arbuthnot was at the high court for the group’s 2019 legal victory. He felt, he said, “almost the same as when the government decided this week to overturn all the convictions. I couldn’t have been more delighted.”

But, he added: “I do worry that this could happen again, and the more so with our increasing reliance on technology, which fewer and fewer people understand because it’s become so complicated.”

Now there is “no shortage of things to be done”. “We need to get the legislation through. We need to get the compensation into the subpostmasters’ hands. We need to bring those responsible to justice. And we need to allow the postmasters to move on.”

Of his own experience, he said: “It’s been intensely frustrating while we weren’t getting traction, and intensely rewarding now that we are.”