Last week, I spoke to Anna Rogers, a Polish-born Londoner who lives in Brixton. She works for a charity called Money A+E, which operates across the south of the capital. It offers advice about debt, benefits and other financial issues to people who are often facing extreme hardship. It is a small set-up, with only four dedicated advisers. Since the coronavirus crisis began, the number of people getting in touch has tripled and is rising all the time.

Rogers spoke matter-of-factly about the defining feature of many who now need her help. “They are people without any income,” she said. Many are migrant workers who have been sacked by small businesses or had cash-in-hand work – in, say, the building trade – suddenly withdrawn. In desperation, some say they would like to return to their countries of origin to be with their families, but that option is cut off right now.

A lot of them have no experience of the British benefits system, and few of the language skills and insider knowledge needed to navigate it. “The universal credit system never worked terribly well,” Rogers said. “But now people are saying that the system crashes, or they can’t upload documents.” Not everyone has internet access, and the sudden closure of public libraries has meant that even fewer people can get online. Even if they manage to do so, there is now an ominous sense that with the system under such pressure, the standard five-week wait for universal credit is bound to increase.

So, for now, Rogers and her colleagues have to introduce people to the most basic kinds of help. One fairly reliable source of food assistance, she said, was the array of new mutual aid groups that have sprung up at the most local level: “Fingers crossed, they can get people some food parcels.” When she spoke about the details of her work, her words had a palpable sense not just of sadness, but of urgency and a clear sense that things were only going to get worse, and quickly.

The fact that we now rarely leave our homes means few people are aware of what is actually going on all over the country. Our field of vision is replete with statistics, and broad-brush warnings about the near future: from the daily death toll to the warnings from big banks of $5.5 trillion in lost global output, to the million or so people said to have newly applied for benefits in the UK. A very human crisis caused by Covid-19 is already here, beyond the illness itself, and it demands our attention.

Play Video 15:41 Life in lockdown: families on the brink – video

To a large extent, it is the result of what many of our politicians have been extolling for years: labour market “flexibility”; a benefits system designed to deter people from using it; and a public sector so underfunded that charities have had to step into the breach. Now, even last-ditch safety nets are fraying fast. The day after my conversation with Rogers, I spoke to Robin Burgess at the Northampton Hope Centre, a project that runs one of the comparatively rare food banks that deals not only with “ambient” items (cans, pasta and other dried goods) but also fresh food. We had briefly spoken a few days before, when he sent me an image of a box of doughnuts covered in mould, sent by one of the big supermarkets – a particularly vivid example, he said, of how low his organisation’s supplies were running, and how useless some of the “help” they received sometimes proved to be.

Donations from the public, Burgess explained, had largely dried up. A lot of fresh food used to come from cafes and restaurants, but they were now shuttered up. Aside from Morrisons, the big supermarkets tended to only directly donate food that was either past or very close to its sell by date, and often of poor nutritional value. And need was inexorably increasing. “We’ve got about two weeks of supplies, or more like 10 days,” he said. “Then we’ll have nothing left.” To some extent, he said, what he was facing reflected the growing crisis for charities and voluntary organisations – who, over the next 12 weeks, are reckoned to face a shortfall of £3.7bn. Last Wednesday, the chancellor, Rishi Sunak, gave them only £750m. And all the time, the social wounds they somehow have to put plasters over are only increasing.

When people draw cliched analogies between the Covid-19 crisis and the second world war, they seem to forget some very obvious things. That conflict was characterised by mass mobilisation. Anyone who could work simply had to: the great upsurge in production that necessarily underpins all-out war demanded it. The coronavirus crisis brings the polar opposite: a new world of confinement, silence, closures, lay-offs and “furloughing”.

If you are able to work from home, relatively free of anxiety about your job and so far untouched by either illness or death, isolation might come with compensations: you may, indeed, be living the Sunday-supplement lockdown dream of craft projects with the kids and demolishing your backlog of novels. But that is the experience of a tiny minority, even if it is informing some of the media’s apparent neglect of what so-called lockdown actually means for millions of people.

Not everyone who instinctively wants the lockdown to be eased as soon as possible is guilty of putting profit before life. It is surely not irresponsible to wonder whether the suspension of everyday existence is not already proving unsustainable, and whether there might come a point when the risks of the virus are outweighed by damage to people’s lives that may prove irreparable. As deaths here and abroad continue to increase, any honest view of our current circumstances must surely be ambivalent – acknowledging that lockdown is necessary, and it is a miracle that the health service has not already buckled, but also that it is exacting a toll that for many people is already unbearable.

That applies not just to those who are falling between the cracks, but to many others who will soon be receiving significant help from the government. Ten days ago, for example, I spoke to a single mother who works for McDonald’s, is paid £9.45 an hour, and has been furloughed. Even if Sunak’s job retention scheme ensures that she receives 80% of her average wages over the previous year, the loss of a fifth of her money will have dire consequences.

She budgets penny by penny and lives month to month. She is already faced with deciding between cooking or heating. Her 13-year-old son has asthma; if the radiators are not switched on in cold or wet weather it gets worse. She spoke with a fierce clarity, and a keen awareness of something she knew far too well: that she is one small part of a social catastrophe so far given far too little attention.

• John Harris is a Guardian columnist