In 2003, Alan Bates, a sub-postmaster in Wales, had his contract terminated due to repeated shortfalls in his post office’s accounts. Was he a crook? Masterpiece’s recent drama Mr. Bates vs. the Post Office settles that question quickly and unequivocally in episode one. The story in the additional three installments recounts Bates’ determination to seek justice for himself and hundreds of other similarly mistreated sub-postmasters. It raises disturbing questions about governmental power, arrogance, and the supposedly infallible technology that increasingly undergirds civil society in the modern world.

If you’ve heard or read about Bates and the Post Office scandal in the UK, you’ll know he acted legally and in good faith, keeping his accounts in good order until the shortfalls began to appear. When that happened, he refused to sign the electronic tally sheet, and that’s when the trouble began to brew. But what the Post Office did in ruining some of its own sub-postmasters’ lives, in refusing to admit any wrongdoing, and in trying to avoid the scandal would shock even the most ardent statist.

The dramatized story begins in 2003 with Mr. Bates (Toby Jones) and his partner Suzanne Sercombe (Julie Hesmondhalgh) serving their customers in Craig-y-Don, Llandudno, Wales. Their business-as-usual gets a severe shock when officials from the national Post Office arrive to shut them down for the shortfalls amounting to thousands of pounds. Since Bates didn’t approve the balance sheets, the government’s goons can’t charge him with theft, but they can and do close the office, leaving the unhappy couple without income, savings, or honor.

However, Alan Bates is no ordinary man. When Suzanne and he move to a cottage in the Welsh hills, he takes all the records, boxes of them, of his office’s dealings with the Post Office, chiefly regarding what he knows were glitches in the national computer system, Horizon. Created by a large corporation called Fujitsu, Horizon connects all the sub-post offices to a central hub where postal transactions are recorded. When the first shortfall occurred, Bates contacted a Horizon-Fujitsu hotline to ask what was up. The answer he got was that the system had operated flawlessly and that he was the only complaint they’d received. As far as Fujitsu is concerned, the case is closed, but Bates has other plans. He sets up a page online where similarly disgruntled sub-postmasters can contact him, and if, as Fujitsu claimed, he’s the only one, the site will remain unvisited.

In fact, other sub-postmasters are having the same problem and not only in Wales. In Hampshire, Jo Hamilton (Monica Dolan) has also experienced shortfalls, only not wishing to rock the boat, she has signed her virtual balance sheets each time. Post Office inspectors arrive and in short order conduct an inquisition. What did she do with the money? Is it in an overseas account? Before she can turn around, she finds herself in court. Another sub-postmaster Lee Castleton (Will Mellor) of Yorkshire discovers a series of discrepancies that soon totals around 26,000 pounds. When he goes to court to get the British justice he firmly believes in, he finds himself the loser, owing the missing funds and added court costs of 321,000 pounds. Sub-postmaster Martin Griffiths (Colin Tierney) receives such public scorn for his publicized chicanery (keep in mind that retirees in the UK collect their checks at the post office) that he’s driven to suicide. Noel Thomas (Ifan Huw Dafyyd), like Bates working in North Wales, gets slapped with a nine-month prison sentence for his shortfalls.

Amid this maelstrom, Mr. Bates, who suspects but does not really know how widespread the trouble is, decides to give notice online to sub-postmasters to meet in a small Warwickshire village, Fenny Compton, to share their grievances. If no one comes, he’ll know Fujitsu was telling the truth. But they do come, dozens. And in the packed local meeting hall, Bates tells the crowd what they need to hear: “You are not the only one.”

In addition, Michael Rudkin (Shaun Dooley), one attendee of the meeting, states that he visited Fujitsu the year before (2008) where a worker blithely and rather naïvely showed him how easy one could hack into a sub-postmaster’s computer and manipulate data. Is this real or a demonstration, Rudkin asked, as he watched. Real as real can be, and in real time. Plainly, this constitutes a breach of faith on the part of Fujitsu and the Post Office.

What I’ve described so far occurs over a period of about six years, but it’s not the end of the ordeal. Jo has contacted her M.P. James Arbuthnot (Alex Jennings) though without much hope of his responding to any effect. She wrong about that. Soon and over the years to come, Arbuthnot will bring the sub-postmasters’ case before Parliament, eventually forcing an outside investigation by Second Sight to get to the bottom of things. Bob Rutherford (Ian Hart), an experienced investigator, quickly perceives the sincerity and honesty of the sub-postmasters and understands all they’ve lost.

Yet he can only go so far. For a time (2012 to 2015), Rutherford’s work, Arbuthnot’s speeches, and the indefatigable Mr. Bates’ steady pressure begin to bear fruit. When Second Sight finds Horizon was faulty, the Post Office agrees to mediation, only to end it two years later (2015) in favor of an “in-house” investigation. The agreement with Second Sight gags Rutherford. To the sub-postmasters’ rescue comes a whistleblower, Richard Roll (Mark Arends) who tells the ugly truth about Fujitsu’s practices. In addition, attorney James Hartley (John Hollingsworth) hears of the case and surmises the Post Office is guilty of breach of contract with its sub-postmasters. When he meets Bates, he tells him that he must have 500 aggrieved individuals to pursue the case. By now you’ll have guessed that Bates finds them.

The Post Office’s chief witness is Angela Van Den Bogerd (Katherine Kelly), a substitute for Paula Vennells (Lia Williams). Vennells and she have stonewalled Bates and company for years, yet when Bogerd gets in the dock to testify, she cannot bring herself to lie to the court. Add Rolls’ damning testimony, and the sub-postmasters have a chance, even against a revered institution such as the Post Office.

The drama ends well enough insofar as the sub-postmasters win their case and are awarded 57 million pounds. Trouble is, court costs and fees eat up so much of it that each person gets only 20 thousand, small compensation for having their lives ruined. Nevertheless, the verdict amounts to a victory.

The cast of Mr. Bates vs. the Post Office is superbly convincing, Jones as Bates in particular. Williams and Kelly provide reptilian villainy in their roles just as Jennings and Hart stand out as chivalrous champions of the downtrodden.

For the record, Alan Bates is still fighting to see the sub-postmasters receive payment equivalent to their lost livelihoods and reputations, and over the last year the government has introduced a bill to overturn their convictions and allow for greater reparations. Did the dramatization help the cause? One has to believe, at the very least, it didn’t hurt. And it’s a story of genuine heroism. Don’t miss it.