The government spending watchdog said that homelessness has increased every year since 2010, with rises in rough sleeping and households living in temporary accommodation, but ministers have been slow to understand the problem or take a strategic approach to tackling it.

The report published today accuses the government of failing to evaluate the impact of its welfare reforms on homelessness, or the impact of the mitigations that it has put in place, and criticises its “light touch approach” to tackling the problem.

According the report there were 77,240 households in temporary accommodation in England in March 2017, an increase of 60% since March 2011. These households included 120,540 children, an increase of 73% from March 2011.

Homelessness at present costs the public sector in excess of £1bn a year. More than three quarters of this – £845 million – was spent on temporary accommodation. Three quarters of this spending – £638m – was funded by housing benefit.

The ending of private sector tenancies has overtaken all other causes to become the biggest single driver of statutory homelessness in England, the NAO said. The proportion of households accepted as homeless by local authorities due to the end of an assured shorthold tenancy increased from 11% during 2009-10 to 32% during 2016-17. The proportion in London increased during the same period from 10% to 39%.

Across England, the ending of private sector tenancies accounts for 74% of the growth in households who qualify for temporary accommodation since 2009-10. In addition, it appears likely that the decrease in affordability of properties in the private rented sector, of which welfare reforms such as the capping of Local Housing Allowance (LHA) are an element, have driven this increase in homelessness.

Today’s report also found that the Department for Communities and Local Government (DCLG) does not have a published cross government strategy to prevent and tackle homelessness. It has, however, acknowledged the scale of the challenge and plans to improve the data the government holds on homelessness.

The watchdog said the DCLG took “a light touch approach” to working with local authorities and does not monitor the content or progress of their respective homelessness strategies.

Labour MP Meg Hillier, who chairs the Public Accounts Committee, said: “It is a national scandal that more and more people are made homeless every year.

“This reports illustrates the very real human cost of the government’s failure to ensure people have access to affordable housing.”

The Local Government Association (LGA) - which represents councils - said local authorities were having to house “the equivalent of an extra secondary school’s worth of homeless children in temporary accommodation every month.”

Councillor Martin Tett, the LGA’s Housing spokesman, said: “The net cost to councils of doing this has tripled in the last three years, as they plug the gap between rising rents and frozen housing benefit.”

It called on the government to support councils by allowing them to invest in building affordable homes and “provide the support and resources they need to help prevent people becoming homeless in the first place”.

Charities called for a national cross government strategy to end homelessness for good.

Jacqui McCluskey, director of policy and communications at Homeless Link, said: “This report sets out clearly the key drivers that have resulted in an increase in homelessness of 134% since 2010, and a 60% increase of households in temporary accommodation.

“The report is clear about the impact of welfare reform on the increase in homelessness and we support the NAO’s call for government to better understand this impact. What is clear is that the freezing and capping of LHA has led to a rise in homelessness and we urge the Government to urgently review the levels of LHA.

“Homeless Link strongly support the recommendations of the report and in particular, we support the call for government to publish a cross-government strategy on preventing and ending homelessness.

“Homelessness can only be addressed by a clear, well-resourced prevention programme, and by a cross-government strategy that addresses the supply of affordable housing and takes into account the role of the unregulated private rental sector, welfare reform and the root causes of homelessness, which are often linked to multiple needs such as mental health and substance use. Homeless Link and our members, offer our support to the government in developing a long term strategy to end homelessness together.”

Matt Downie, director of policy and external affairs at Crisis, added: “The NAO fully acknowledges what we already knew, that homelessness has got drastically worse since 2010-11. The NAO demonstrates that while some parts of government are actively driving the problem, other parts are left to pick up the pieces, causing misery for thousands more people, as they slip into homelessness. This is in part down to government decisions on Local Housing Allowance, making housing unaffordable for those in greatest need, while councils struggle to rehouse people.

“As the NAO shows, more is being spent leaving people in limbo as they are placed in temporary accommodation, while less is spent on homelessness prevention, social housing and new affordable housing, which makes little sense. While the Homelessness Reduction Act coming into force next year will address this preventing many from becoming homeless in the first place, it must be implemented with cross-government working and a genuinely affordable housing supply. Furthermore, the government must fully assess the impact of its welfare reforms on homelessness. As our homelessness monitor series has repeatedly shown, welfare reform has greatly impacted homelessness across the UK.

“While a lack of cross-government strategy has undoubtedly fuelled the rise in homelessness, the forthcoming Homelessness Reduction Taskforce should help to ensure this issue is addressed. But this taskforce must strive to ensure that no part of government is causing problems while other departments are working hard to resolve the situation at hand. Working together is now the only way we will move forward to end homelessness once and for all.

“Crisis is now calling for Parliament to scrutinise these findings through the Public Accounts Committee.”