I have just read a beautiful book about something truly obscene. Full of lovely pictures and occasional bits of text, it’s the kind you might read with your four-year-old. It shows a little girl and her mum as they visit a food bank.

It’s a No-Money Day is narrated by the daughter who sees how her mother worries over every penny, while shielding her from the painful stuff. “There’s no more cereal, so I have the last piece of toast. Luckily Mum isn’t hungry,” the girl says; and you know the biggest thing Mum will have for breakfast is her own little white lie. When they reach the food bank, the child tucks into biscuits and squash while her mother sags like a balloon from which the air has escaped.

Only just published, it is believed to be the UK’s first picture book about food banks. And, while the subject has been handled compassionately by the prize-winning author Kate Milner, I can’t help but see that landmark as a disgrace – for all of us. It is the watershed moment when Britain’s food banks go from newspaper headlines to a subject that teachers cover in classrooms; the moment at which mass destitution is no longer a badge of political failure but is instead accepted as part of British life.

As recently as 10 years ago, child poverty was an evil that prime ministers Tony Blair and Gordon Brown both vowed to abolish; now it is something you shamefacedly explain to your child as he or she nestles in your lap.

Picture books used to be small worlds where kids could dream about farmyard animals and cuddly monsters; today they teach about the vast number of people that their parents’ generation treat like dirt. In 2016 David Cameron casually dropped the legally binding targets to reduce child poverty – and those figures jumped. More than 4 million children live in poverty in the UK today – or nine kids in every classroom of 30. At the start of this decade, the Trussell Trust ran just 57 food banks, giving 14,000 food parcels a year to children. It operated 428 food banks last year, handing nearly 580,000 parcels to children. This is a charity that sees itself as temporary. Our failure as a society is making it permanent.

The book shows a little girl and her mum as they visit a food bank. Illustration: Kate Milner

In one of the richest societies in human history, such figures should mortify us, yet the Westminster classes take them as unremarkable. They hardly ever trouble TV bulletins or newspaper columns, while Conservative cabinet ministers such as Michael Gove sneer at the impoverished for not being able to “manage their finances”.

As the UK staggers into a rage-filled general election, well-lunched gasbags will solemnly inform us that this is an election about “getting Brexit done” – while ignoring the cuts, the broken economy and the other causes that helped to drive the Brexit vote of 2016. Dealing with those causes would entail being winched out of the deep embrace of the TV studio sofas, tearing out the IV drip that feeds them the untreated bullshit of No 10 “sources”, and seeing more of the country than could ever be conveyed in a fleeting vox pop.

If the experts did that, they would confront a society where levels of deprivation once considered shameful are now treated as normal; where what was scratched together just a few months ago is now relied on as part of the new, ad hoc welfare state.

This week I went to Colchester, in Essex, to see something both brilliant and saddening: a Munch Club. In a small scout hut on the postwar Monkwick housing estate, 45 children and their parents were getting a free lunch to ease the expense of half-term holidays. Tiny kids were burrowing into mountains of chicken nuggets and chips before collecting chocolate cake in custard. There’ll be Munch Clubs across the town this week, run by volunteers and depending on donations. They’re the idea of Maureen Powell, a local pensioner with a sharp blond bob and a smoker’s laugh. She started here just a year ago, and by Christmas plans to run no fewer than six Munch Clubs. People keep asking her to lay on more, and she thinks she knows the number-one reason why.

“Universal credit!” she shouts, putting the blame squarely on the policy spawned by that MP down the road in Chingford, Iain Duncan Smith. “You have to wait five weeks for any money to turn up; and they mess you about. They [the government] give you a [starting] loan, which they take out of your benefits. It’s just debt upon debt upon debt.”

To keep the clubs going, Powell often raids her state pension while her small home is crammed with four freezers and three fridges to store supplies. As indicated by the crutch with which she hobbles, she has her own issues – arthritis, asthma and secondary multiple sclerosis. Let me speak plainly: Powell is a hero, yet nothing about this system feels like an adequate replacement for a proper welfare state. Except that’s not something the UK can say it really has any more – not when the state prefers literally to melt 50p pieces of hubris rather than keep citizens from starving.

‘Luckily Mum isn’t hungry.’ Illustration: Kate Milner

At one table sit Gary and Rebecca, surrounded by their five kids. She raises the children, while he stacks shelves at a supermarket. When his wages hit their bank account, the money is all gone on bills by that same afternoon. Their universal credit top-up is just not enough.

If they weren’t at the Munch Club, “neither Gary nor me would eat anything till dinner, so as to leave more for the kids”, says Rebecca. How do they cope with the hunger? “You get used to it,” she shrugs.

Their children get neither sweets nor treats, and their parents can’t afford to take them to Colchester zoo or the fireworks. I think about the classroom tradition of talking about what you did in your holidays and wonder what these kids say. I wonder how tough things get at home, and how much they overhear.

Not far away is Bevan Close, a reminder of the Labour minister who built this estate. Nye Bevan wanted communities founded on fairness, where “the doctor, the grocer, the butcher and the farm labourer all live in the same street”. What has replaced his vision? When Cameron entered No 10, Colchester borough council received £11m a year from Whitehall. It’s a sum that has dropped and dropped: this year it is £275,000; next year, precisely zero. Common lawns on the estate used to get cut every month; now it’s only three times a year. Police officers used to patrol on foot; now, says councillor Dave Harris, “the only time a cop car turns up is when there’s really bad news”. The large NHS clinic, where parents took newborns to be weighed, is now shuttered up.

We could talk about austerity or tough choices, but something far more profound has happened here – a poor area a couple of hours from Westminster has been systematically stripped of some of the rudiments of civilised life. This is the new normal for swaths of Britain: where a man can be declared fit for work shortly before dying; where headteachers have to beg parents for toilet roll; where children must rely on a sick pensioner to keep them fed out of term time.

That’s what this election is really about: not Brexit, not Boris v Jezza, but how we define a civilised society.

• Aditya Chakrabortty is a Guardian columnist