I have a friend who works almost every waking hour, mainly to pay the rent. Her landlord lives on a beach, 4,000 miles away. He seldom responds to her requests, and grudgingly pays for the minimum of maintenance. But every so often he writes to inform her that he is raising the rent. He does not have to work because she and other tenants work on his behalf. He is able to live the life of his choice because they give their time to him. As there is a shortage of accessible housing, they have no choice but to pay his exorbitant fees.

People say, ‘I work for Tesco' or, ‘I work for Deliveroo', but the reality for many is that they work for their landlord

Rents charged at such rates – far beyond the costs of capital and maintenance – are, in these circumstances, a form of private taxation, levied by the rich on the poor. The penalty for failing to pay this tax is arguably greater than the penalty for failing to pay taxes owed to the state: eviction and homelessness. People say “I work for Tesco” or “I work for Deliveroo”, but the reality for many is that they work for their landlord. While the average mortgaged household spends 12% of its income on housing, the average renting household spends 36%. I have met plenty of people who hand over 50% or more.

The UK has become a paradise for landlords and hell for tenants. Buy-to-let mortgages, easy evictions, uncapped rents, generous tax breaks and the replacement of social housing with housing benefit (a bill that now amounts to £22bn a year, much of which is paid to private landlords) have turned the rental sector into a licence to print money, at the expense of both tenants and taxpayers. In the 13 years between 2002 and 2015, average wages for people who rent rose by 2%, but their rents rose by 16%.

Landlords get away with providing unfit and dangerous accommodation, and tenants have a powerful incentive not to complain to the local authority, as 46% of those who do so are summarily evicted. The government’s promise to repeal section 21 of the 1988 Housing Act, which enables owners of property to evict tenants without good reason, will achieve little if it does not come with a cap on rent rises: otherwise landlords can engineer de facto evictions by hiking the price.

The effects are devastating not only for people’s finances but also for their family life and peace of mind, as Catrina Davies reminds us in her beautiful, elegaic book Homesick, published this month. After a childhood clouded by her father’s bankruptcy, the subsequent loss of the family home, destitution, divorce, chaos and mental illness, she finds herself on the wrong side of the magic line between those who own and those who don’t. She is engaged in an endless struggle to lead a good, fulfilling life, without being crushed by the demands of rent.

After living in a tent, a van and a static caravan, she rents a tiny box room in a crowded, angry house in Bristol for £400 a month. While she struggles to meet her bills, her landlords blithely travel the world. Eventually, it all becomes too much. She flees into a collapsing shed in Cornwall, without planning permission, electricity or water. She now lives on the wrong side of the law, under corrugated iron and decaying timber, in extreme precarity, but with a measure of freedom she has not been able to find elsewhere.

She is surrounded by the dysfunctions of Britain’s property market. A miserable, pokey flat comes up, but there are no available jobs that could possibly cover the rent. Buying is impossible: the average price of a house in Cornwall is £206,000, while the average wage in the county would permit her to borrow £51,000.

This disparity is partly explained by the vast market in second homes and holiday homes. In the UK, while 320,000 people are officially homeless (and many more are invisibly sofa surfing or sleeping in sheds or cars), one in 10 adults now owns more than one home. These owners are overwhelmingly rich and middle-aged or elderly. During the first 10 years of this century, the number of homes standing empty for most of the year rose by 21%.

Davies encounters an almost feudal economy, in which non-owners work for the owners. Some of the employers – offering casualised work at the minimum wage cleaning and servicing holiday homes and staffing cafes and car parks – are also the local landlords, who set rents their own workers cannot afford. The economy is sustained by people living in tents, vans and caravans. She notes that “basic needs can be satisfied very cheaply when you don’t have a landlord to support”. But landlords have become punitively expensive to maintain.

The folk theory of crazy rents and mortgages is that they are the result of too few houses and too many people. But one of the amazing facts of our time is that the UK has more bedrooms per person than ever before. Throughout the boom in house prices, the number of dwellings here has been growing faster than the number of households. There is plenty of housing – for the rich. But a series of outrageous policies ensure that it remains inaccessible to the poor. There are council tax discounts for second homes and holiday homes, and for single people in large houses. The capital gains tax on second homes and investment properties is lower than income tax. Why work if your extra homes earn more than you do – even if they are left empty?

If the number of homes had grown by 300,000 every year since 1996, the average house today would be only 7% cheaper. This is because of the economic decisions successive governments have made, ensuring that our surplus homes – and surplus rooms – are inaccessible to those who need them most. Yes, we need to build more social housing, but even a massive programme would take many years to counteract the effects of our pernicious system. As the Land for the Many report (commissioned by the Labour party and edited by me) points out, we also need explicit policies to stabilise house prices and prevent homes from being treated as financial assets. Among them are stiffer restrictions on evicting tenants and raising rents, stronger regulation of buy-to-let mortgages, a national register of landlords, with iron rules ensuring that the homes they offer are safe and fit, and higher rates of capital gains tax for additional homes.

We will need private landlords for the foreseeable future, and they should be able to make some money from their property. But they cannot be allowed to use their position as owners of a limited and non-reproducible resource (the land on which their houses sit) to extract private taxes from people much poorer than themselves. We claim to be a nation that values freedom. But freedom is currently the preserve of the rich.

• George Monbiot is a Guardian columnist