Last Friday, John beat a system designed to beat him. He took on a secretary of state, a giant business and an infamous bureaucracy – and won. His story comes with a happy-ish ending; yet the more I turn it over, the angrier I get.

First, there is the humiliation and desperation dealt to a decent man who did nothing wrong. Then there are the tens of thousands who are not as lucky as John. Perhaps they include your family, your friends or your neighbours. Whoever they are, they are being driven further into sickness and poverty by our government. Their crime? Being disabled.

Just like John. His story begins and ends with two brown envelopes. The first came last October and contained the news that he’d been judged fit for work. This was despite his major injuries sustained from an attack 30 years ago; despite even a short walk leaving him reeling with pain; despite how even being dosed up with tramadol won’t get him more than three hours’ sleep a night. John had submitted all this evidence in good faith to the “healthcare professionals” and “decision-makers” employed by US giant Maximus and the Department for Work and Pensions (DWP). But they decided that he was not, to use the latest term from our governors in No 10, “really disabled”.

It was at that point I wrote about John on these pages. He’d been robbed of one of his key benefits – employment and support allowance – and was now being forced through the cruel and stupid bureaucracy of demonstrating he was looking for work that he could not possibly do. Friends told me he’d “collapsed”, and when we spoke he kept breaking down crying. We picked John as a pseudonym, so worried was he of reprisals. His was just one of the real-life stories that proved the grey horrors depicted in Ken Loach’s and Paul Laverty’s I, Daniel Blake – which this month won a Bafta – were not made up.

Things got even worse afterwards. His GP wrote saying he was in no state to look for work, to which the jobcentre responded by taking away his jobseeker’s allowance. For most of the run-up to Christmas, he was living off his disability living allowance: just under £50 a week to cover heating, groceries and everything else. While friends lent him cash, he also racked up a big overdraft with his bank. He felt as if he was drowning. “I was going under.”

And then the Child Poverty Action Group (CPAG) contacted me to offer John help. One of its advisers, Martin Williams, found that the DWP actually owed John thousands in unpaid benefits. And last week, John and Williams went to an appeal hearing in central London. Despite fierce questioning from a doctor (who had “an air of incredulity about him”, remembers Williams), John held it together. Then came the second brown envelope on Friday, overturning the crazy verdict that he was fit to work and restoring his ESA.

For the first time in five months, John can “finally look ahead”. This modest, gentle man, who lives quietly without smoking, drinking or eating out, describes what the extra money will mean to him. He won’t need to borrow off the bank or anyone else. The literature graduate might even be able to splash out on the occasional paperback.

A bit of good news in the dying days of winter, you might call it. But I cannot use that term for a story of a man driven nearly to destitution and forced to fight for months merely to restore his rightful benefits. Nor can I stop thinking about all the people who aren’t lucky enough to come to the attention of a national charity with highly experienced welfare advisers.

Seven years of cuts, and the near-scrapping of legal aid, means there are far fewer people like Williams and much less help for those deprived of their benefits. Among the letters I received after my first article about John were a number from people who’d also been declared fit for work but could not face going through the call centres and tribunal hearings, the reconsideration and the appeal and the months of having to prove how sick they were. Nor were they going to go through the humiliation of the jobcentre: they were simply subsisting on a few quid a week.

When I asked the DWP for a comment, it pointed out that only 4% of all ESA work capability assessment decisions are overturned. That may be as much a commentary on the opacity of the procedure, because over 60% of those decisions that are actually taken to appeal are successful. At CPAG, Williams thinks he handles 30 such appeals each year. Over the past three years, he has won all but one.

None of this is an accident. It is a system that has been set up by a government that wants to deprive poor people of money that is owed to them, even while it hands cash to the richest. This week ministers will formally announce that disability benefits will be cut by a further £3.7bn a year. People with mental health problems, who need help just getting out of the door, are now to be judged not “really disabled”. This from the same party that has spent seven years slashing corporation tax, so that big businesses now pay nearly £11bn less into the public purse. What’s more, Theresa May has vowed to cut these taxes even further.

This is the same party that has tried to make the appeals process even harder for people such as John, so that claimants merely file papers rather than get to present their case in person. The same party that allows huge delays to mount up in assessments for personal independence payments, which means people with disabilities are deprived of both that and a range of other help.

Think about having to live on a few quid a week, of being interrogated over the possibility of any more, of being cut adrift from the rest of society for no other reason than your disabilities. Then think about the consequences. The people who can’t get by on nothing. Those who are driven to the wall.

I have lost count of the number of people with disabilities who have told me of friends who’ve contemplated suicide or who have even gone through with it. It is not an overstatement to say they have been killed by a government that wants to punish the vulnerable and reward the rich.

When we speak, John shows some evidence of survivor’s guilt – of wondering why he’s got through when others have been ground down. “I don’t feel like I’ve been through a proper process of the law. I feel like I’ve been lucky.” This is what it takes to survive as a poor person in one of the richest societies in history: huge reserves of personal strength, the tenacity to fight like mad, and the ability to get by on a pittance.