Walk the streets of any city in Britain in 2016 and before too long you are likely to come across a rough sleeper. After a long period of decline, numbers have been on the rise since 2010; in London, the number has more than doubled in the last decade.

As rough sleeping has become increasingly visible, it has resurfaced in the public debate. But too little of this debate has been focused on what we as a society can do to prevent people from having to sleep rough; too much on debating whether individuals should give cash to beggars on the street; or passing judgment in cases where beggars turn out not to be as destitute as people assume, even though they may face serious mental health or drug addiction problems.

The individual stories we publish this week in the New Review show there is no one way to become homeless. Too often, it happens as a result of a multitude of factors such as relationships breaking down, mental health problems, drug or alcohol dependence or tenancies coming to an end.

Rough sleeping is the sharpest end of myriad social dysfunctions: in the housing market, in the welfare system, in the provision of services for the most vulnerable and in the immigration system.

The most common trigger for homelessness is being unable to find a new home when a tenancy comes to an end. Too often, we talk of the housing crisis purely in terms of home ownership, but the lack of affordable homes to rent is just as serious.

By expanding the definition of affordable housing to include relatively high-cost home ownership options and forcing councils to sell off high-value council housing to pay for the right to buy for more affluent housing association tenants, the government’s housing and planning bill risks making this worse.

Welfare reform has compounded the difficulties of finding somewhere to rent on a low income. The historical link between housing benefit and actual rents has been broken, with housing benefit frozen for the next four years, and support for housing costs set to be withdrawn altogether for people aged 18 to 21. Capping housing benefit while undermining the supply of homes for affordable rent will only serve to increase homelessness. For those on out-of-work benefits, benefit sanctions do not take into account the risks of triggering homelessness: two-thirds of councils in England say welfare reforms have increased homelessness in their area.

Local services for people with mental health problems and drug and alcohol addiction have also suffered as a result of cuts, increasing the risk of homelessness. And once someone becomes homeless, there is evidence of stretched local authorities unable to meet their duty to provide support: “mystery shopping” by the homeless charity Crisis found several councils turned away people claiming to have learning disabilities and mental health issues .

In London, immigration has been a factor: 35% of rough sleepers are from eastern Europe. In theory, their right to live and work in Britain is contingent on them being able to support themselves financially; in practice, this is difficult to enforce.

The long period over which rough sleeping was in decline shows there is nothing inevitable about it. But reducing it requires investment not just in short-term fixes such as hostels and day centres, but in the mental health and drug rehabilitation services that can prevent someone from becoming homeless in the first place; in the longer term, intensive support is needed to help them make a new start.

Even this is not enough, however: we cannot ignore the fact that homelessness and rough sleeping are also symptoms of our increasingly dysfunctional housing market. Government is simply not investing the same energy and resources in expanding the supply of affordable rented housing as it is in home ownership subsidies, which risk further inflating the market anyway.

Rough sleeping remains a tragically visible barometer of the nation’s social health. The fact that it is edging upwards is a symptom of the harsher place Britain has become for many people surviving on a low income or facing challenges such as poor mental health or drug addiction.