There's a calculation that I've begun to do whenever I find myself visiting an events hall, or a posh set of offices, or the home of someone over 40. I take in the number and size of the rooms and work out how many of the legion poor and peripatetic young people I know could live in the extra space. Often, I find myself making small talk with people in expensive jackets while instinctually trying to gauge where I'd put dividing walls, loft beds and electric heaters, guessing how many wasted square feet could be used to shelter and nurture friends, comrades and strangers who were abandoned at the crunchy end of the credit crisis.

It's easy when you get the hang of it. The second floor of the RSA [2], for example, could comfortably house ten young families. The ladies' loos at Thomson Reuters could sleep 16 single people if you knocked out some of the sinks. My own father's bachelor pad could squeeze in eight bodies at substantially higher than the living standards most impoverished London renters enjoy. I'm serious. There's only so much space to go around and with millions of young, poor and precariously employed people struggling to hang on to accommodation, the notion of sharing it out more fairly is hardly a crazy communist plot.

Housing isn't a particularly sexy subject to write about -- unless you're one of the people to whom it matters. People who don't know what it's like not to be able to afford a safe, comfortable place to live, including the vast majority of media commentators, can't grasp how it feels to be unable to control your living space, to worry that the coming cuts to housing benefit might mean eviction and destitution. Last night, I stood in a mould-stained tower-block bedroom not much larger than a club toilet cubicle and tried to work out if I could bear to make this my home.

I'm currently without secure accommodation for the fourth time this year, and trying desperately to find another hovel within commuting distance of my job. It's draining, and it's debilitating, and it's a daily experience for millions of people with the misfortune to be low earners, or immigrants, or under 30. In 21st-century Britain, the middle-aged rich control the property and the power, and there's no room for the young, the poor and the difficult. There's quite literally no room.

For the past few months, I've been sleeping on friends' sofas, meeting copy deadlines on intercity coaches, attempting to scrape together the money for a deposit while house-hunting. I've been relying on the kindness of strangers and the occasional serendipitous seduction to make sure I've had somewhere to plug in my laptop. I've been insecurely housed for three years now. In 2008, when I started to write about politics, I was living in Turnpike Lane with between five and seven other unemployed and precariously employed young people, crammed into a dirty, run-down house meant for three.

I wrote because I was angry and wanted to escape. I wrote because when I was writing, I could block out the sound of the rats in the walls and the racket of a violent, drunkenly abusive housemate rehearsing destructive relationships in my kitchen. I wrote because when I was writing, I didn't have to watch my disabled partner, rejected from sickness benefits for the fourth time and living on money from sex work, slipping into a haze of drugs and depression. I wrote so furiously and obsessively that it got me a job, and then a better job; I began to earn real money, although not enough to stop us all becoming homeless again.

I've blogged about a lot of things this summer, but I've not yet been able to write about my living situation. I've felt ashamed. Like many young people, I've felt that not being able to house myself securely means that I've somehow failed as an adult. Living in shitholes for a while has always been part of the adventure of being young and fancy-free but, today, more and more of us find ourselves unable to progress from that stage to the point where we can afford central heating and a bed that's not made out of packing crates.

As the recession has clamped down on our futures, many of us are failing to make the transition to real adulthood, in a world where maturity and respectable citizenship are defined more than ever by property ownership. The quarter of young adults who still live with their parents learn to internalise the special contempt that British culture reserves for those who can't afford their own space.

For the rich and the middle-aged, property remains a commodity fetish: a house is an asset, a tool for wealth-creation, not a home. Every human being needs a safe place to live, but the orthodoxy of late capitalism insists that basic human needs such as shelter and a measure of autonomy are commodities to be bought and bartered, and if the poor are priced out, too bad. That this financial narrative recently begat the most destructive recession in living memory has not been enough to persuade the new government to build one solitary extra stick of social housing.

This weekend, I have to move out of my temporary accommodation and I have no idea where I'll go. I'll probably be OK eventually; with my expensive education and nice writing job, there's every chance that in 20 years, I'll be installed in a flat in Kensington with a study, a coffee machine and a Shar Pei named Olivia. This prospect is supposed to make me want to work harder, complain less and polish my CV to parade gloss, so that I can be one of the lucky ones who gets to escape the rats and the rot and the rage. Instead, it makes me want to walk into the Department for Work and Pensions and set myself on fire.

When all you have is a roll-up mattress, it's hard to stay an armchair revolutionary.