The Post Office Horizon IT scandal may well be "the worst miscarriage of justice in recent British legal history".
Jason Beer KC, counsel to the inquiry which has been investigating the scandal, did not put it this way lightly.
After four hard-fought years, senior executives reduced to tears, and countless heartbreaking stories of the damage caused to the personal lives of sub-postmasters, the Post Office inquiry has finished gathering its main evidence.
It was set up to investigate why more than 700 sub-postmasters were wrongly prosecuted and deemed criminals for theft and false accounting - when in fact it was the faulty Horizon IT system made by Fujitsu to blame.
This is why Mr Beer put it so strongly.
The inquiry has been looking to establish when the Post Office knew sub-postmasters weren't responsible, why the Post Office never overturned prosecutions, and if there was a cover-up.
Throughout the process, we heard alarms were raised by external lawyers, people within the Post Office, the media, and most of all campaigners.
Some of the appearances at the inquiry have been shocking, revelatory and emotional.
Here, Sky News explores some of the key moments from the inquiry.
'Subbies with their hands in the till'
No exchange quite compared to an email from the Post Office's former managing director Alan Cook, who insisted it was sub-postmasters to blame and not technology.
This was despite victims consistently denying involvement.
It was during his evidence, that an email was read out - which said account shortfalls were down to "subbies with their hand in the till [who] choose to blame the technology when they are found to be short of cash".
Mr Cook said it was an expression he would "regret for the rest of my life".
He also highlighted systemic failures within the Post Office.
He claimed he was "unaware" the Post Office brought prosecutions - and that it did not feel like the Post Office "had a crisis on its hands".
'I think you knew'
The appearance of Paula Vennells was probably the most high profile of the inquiry.
ITV hit drama Mr Bates vs The Post Office put Ms Vennells - the former Post Office chief executive - at the very heart of the scandal.
At the inquiry, she was reduced to tears more than once as she apologised for her role.
A recent text exchange with Dame Moya Greene, the former chief executive of Royal Mail, was one of the most damning moments for Ms Vennells - which weakened her defence of not knowing what was happening with prosecutions.
Dame Moya texted Ms Vennells after the airing of Mr Bates Vs The Post Office, which reinvigorated interest in the scandal early this year, saying: "When it was clear the system was at fault, the Post Office should have raised a red flag. Stopped all proceedings. Given people back their money, and then tried to compensate them from the ruin this caused in their lives."
When Ms Vennells replied that she agreed, Dame Moya said: "I don't know what to say. I think you knew.
"I want to believe you. I asked you twice. I suggested you get an independent review reporting to you. I was afraid you were being lied to. You said the system had already been reviewed multiple times. How could you not have known?"
Dame Moya continued: "I can't now support you."
"I have supported you. All these years... to my own detriment. I can't support you now after what I have learned," she added.
Dame Moya also backed this view up when she gave evidence to the inquiry, saying: "I think she knew on the basis of the evidence that has emerged at this inquiry that there were faults in the system."
As was to be expected, Ms Vennells denied any knowledge of issues or miscarriages of justice and called the situation "complex" adding that there are "some things I did not know… I wish I had known".
Post Office told to stop prosecuting - but continued
The Post Office was told years before convictions were stopped that a key witness used to prosecute sub-postmasters was unreliable.
The barrister Simon Clarke told the inquiry he was advised this after he found serious errors and "an almost religious panic" about the Horizon IT system.
He wrote a key piece of legal advice in 2013 that made the issue with past prosecutions clear to executives.
Mr Clarke had branded Fujitsu's Horizon IT architect Gareth Jenkins as a "tainted" and "unreliable witness".
In a dossier commissioned by the Post Office, Mr Clarke said Gareth Jenkins had breached his court duties by failing to disclose known issues and bugs with Horizon.
Those known issues may have allowed sub-postmasters to challenge their convictions and have their criminal record overturned.
Mr Clarke also insisted the Post Office shouldn't use Gareth Jenkins as a witness and recommended all prosecutions be reviewed.
But, as has been so often the case in the story of the scandal, the Post Office ignored this advice by not reviewing prosecutions and continuing to prosecute sub-postmasters until 2015.
Mr Jenkins is currently being investigated by the Metropolitan Police for suspected perjury.
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Tap hereThe pregnant woman sent to prison in 'test case'
Every story told by the sub-postmasters affected by the Post Office scandal highlighted the sheer scale of the damage caused to their lives.
Sub-postmaster Seema Misra's conviction was hailed as "brilliant news" in an email between Post Office executives, the inquiry revealed - this being despite her sentence including 15 months in jail and having to serve four months while pregnant.
The inquiry also heard that executives and Post Office lawyers treated her as a "test case" - if her prosecution was seen as successful, then senior officials stated it proved Horizon was "robust".
In response, Ms Misra told Sky News: "How can they do a test on a human being?"
"I'm a living creature," she added.
When Mr Jenkins - the expert who testified in court defending Horizon - was called to give evidence to the inquiry he apologised to Ms Misra.
Mr Jenkins said he did not understand his duty of disclosure as an expert witness at the time - and fervently tried to diminish the idea that he misled the court or withheld information.
Ms Misra rejected his apology.
What's next for the inquiry?
The inquiry's last phase will begin in the autumn - this will look at the Post Office's current practices and make recommendations for the future.
A report will also be published - though when this will be specifically is unclear.
Inquiry chair Sir Wyn Williams has previously said it will be "as soon as is reasonably practicable" after hearing about current practices in September.
The chair may also refer executives and those who have worked at the Post Office and Fujitsu to the police - should he think any criminal investigations are needed.
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