“When I come home I feel this sense of doom,” Jenny says. “I can’t have the window open because I’m on a noisy, polluted road, and I can’t have the blinds open because there’s a bus stop right there. I’ve had people weeing on my doorstep, doing crack outside my front door.” There are practical challenges. Jenny eats on her bed, which, like her clothes and everything else she owns, smells of whatever she cooks. Without proper storage, anything out of place can make the flat feel chaotic. The hum of the fridge keeps her awake at night.

“I think that even if someone didn’t suffer from anxiety or depression, living in this flat would affect them mentally,” she says, wondering how she might start to recover in a house like this. “You feel it – oh my God, the air is so … heavy.”

… But standards and ideals can get blurred in a vicious economic cycle. Ministers relax planning rules to enable more building and development. Developers and landlords find profitable loopholes in those changes. Local authorities, desperate for alternatives to their own dwindling housing stock, direct residents to those landlords, fuelling further exploitation at a time when councils also lack resources for planning and building control. Residents, often faced with homelessness, endure the cramped results, until society notices and someone writes another report.

“My concern is that people are becoming inured to something that they shouldn’t have to put up with,” says Julia Park, the head of housing research at architectural firm Levitt Bernstein. She has written a history of space standards and is surprised by how little we consider the effects of domestic confinement. “When you’re living in smaller and smaller flats, you reach a point where it makes sense to take out the walls because one big room feels nicer, but I think that implies a lot of compromise we’re not examining,” she says. “Some of these flats pose threats to physical health, but, in small spaces, it’s going to be mental health that is most affected.”

… Park, who advises local authorities, laments the way sleeping, cooking and washing are increasingly viewed as the only functions of a dwelling in a housing market where a living room is becoming a luxury. She is especially worried about the types of homes that have emerged in the gaps in policy. This summer, she noticed a seven-floor former office block in Croydon, in south London that had been divided into flats. Planning records showed that each of the six upper floors in the building had been converted into 10 studios, including single flats of just 13 sq m.

By current standards, these flats are barely a third of the recommended size. Park was instrumental in drawing up the “nationally described space standard”, a nationwide metric implemented by the government in 2015. It recommends 37 sq m for a one-person, one-bedroom flat; a two-person, one-bedroom flat should be 50 sq m.

Park was surprised that the government had agreed to the recommendations, given its austerity policies. “The compromise was that it is optional,” she adds, estimating that fewer than half of councils have adopted it. Even when they do, it only applies to new buildings or developments that go through the planning system, but not to a range of “permitted developments”. So, for a relatively small investment, the owner of an office building, for example, can convert it into self-contained flats with only “prior notification”.

Ben Clifford led a team that visited more than 500 converted office buildings for a report published last May by the Royal Institution of Chartered Surveyors. “We were shocked by how many of these flats were of a very poor quality,” says Clifford, a senior lecturer in spatial planning and government at University College London’s Bartlett school of planning. In one, Clifford called the fire brigade after spotting walls dividing flats made only of plywood. “We spoke to one resident who was in a tiny one-bed flat with two children and no balconies or open space,” he says. “Another woman, in an 80s office building, said it just wasn’t very nice to live in a flat with big tinted windows that don’t open.”

In the so-called “lockdown” model, meanwhile, rogue landlords are converting family homes into tiny studio flats specifically to attract tenants aged 35 or over who, like Jenny, claim the higher housing allowance for a self-contained dwelling. By including a token shared facility, such as a tiny kitchen – or by ignoring rules altogether – these landlords also bypass planning permission by treating such developments as flat-shares (another permitted development). The rental income from six cheaply built studios is multiples of that for a three-bed flat share in the same house – and it is the taxpayer who lines the landlord’s pockets. “It’s basically the warehousing of homelessness,” says Jon Knowles, a computer analyst and campaigner who has recorded hundreds of such developments.