The cost of renting in your 20s? £66,800 Together they have formed a rapidly expanding army of buy-to-let investors; a giant Hoover, sucking up young people's wages and preventing them from getting on the housing ladder themselves. Many of these tenants in their 20s, 30s and 40s are earning very respectable livings. But still, spending vast proportions of their wages on rent - some 40pc of them are forking out more than 40pc of their income on rental bills according to a recent report. Telegraph Money analysis of five years" worth of HomeLet renting statistics and Savills inflation projections shows 20-somethings in the UK can expect to pay £66,800 in rent to landlords by the time they are 30. When laid bare these costs are crushing for young tenants. In their eyes, they are effectively flushing a sum worth twice the average UK first-time buyer deposit down the toilet. But in the eyes of their landlords they are profitable cash cows funding the next yield-ripe purchase. Unsurprisingly, £66,800 doesn't even touch the sides when it comes to the amount the average 30-year-old in London will have already spent on rent. In the capital, tenants in their twenties can easily expect to hand at least £100,000 to landlords if they are constantly renting. As the cost of renting continues to rise in relation to young people's wages, accepting the loss of these eye-watering sums is pushing them further away from achieving the financial security they associate with being a "proper adult." For example, having six month's salary in the bank for emergencies, and building enough for a house deposit. Tenants: What percentage of your salary do you spend on rent? A sum of £66,800 is more than more than most people will ever save in their lifetimes. By contrast, the majority under 30"s have never had more than £1,000 in savings to their name. There is nothing wrong with renting as a concept and it works well in other countries like Germany where rental prices and conditions are closely regulated. But the UK system has become capitalism on steroids; a beast that is forcing unreasonable strain on young people's finances. Our country's buy-to-let craze is sucking the life out of young people's current and future financial security. And to boot, a lack of house building is creating a desperate undersupply of housing, further exacerbating the problem. Renters in the UK are approaching breaking point. Unless they have wealthy parents to subsidize them, young people are increasingly likely to resort to desperate measures keep accommodation costs under control. For example, a fifth of sharers in London are turning their living rooms into extra bedrooms to reduce rent, and hanging out with friends in corridors and landings instead. In a bid to bolster their all-important yields, some landlords are allowing the overall conditions of these rental properties to deteriorate. Millions of rented homes in the UK are in serious need of attention. Hundreds of thousands of these tenants who ask their landlords to fix a problem end up wishing they hadn't, as in a cruel twist, they face "revenge" eviction, according to Shelter, the housing charity. Perhaps this is why swathes of them are finding adult independence all too much, quietly retreating to their childhood bedrooms instead. Around 3.3 million (25pc) of them now live under their parents" roofs according to official figures, with the proportion due to rise by 2020, according to the Joseph Rowntree Foundation. On Friday the Commons will debate a private members bill to ban "revenge" evictions. Last night, a small protest group of around 100 demonstrated outside Parliament to convince MPs to stay in Westminster for the vote. This is not just something that's been cooked up by policy wonks - it's a real threat that could affect the lives of millions of renters in the UK. The generational unfairness of Britain's broken housing market is at the top of young people's political agenda. But you wouldn't know it, judging by how many of them bothered to leave their damp and overcrowded flatshares to take to the streets and fight for their rights outside Parliament on Monday. Instead you'll find them airing their concerns on Twitter, in the blogosphere, and occasionally writing articles such as this. But you'll never hear a peep out of the vast, voiceless majority. The sad truth is that most are either quietly bubbling with resentment or living in denial, while their twenties, and £66,800 silently slip away. Think its time for change in the UK housing system? Email katie.morley@telegraph.co.uk