Homelessness in England has been growing for seven years and is now a "national crisis" – yet the government has been "unacceptably complacent" about the issue, a damning report from MPs has found.
The cross-party public accounts committee said ministers had failed to both monitor the true extent of homelessness and set out a clear strategy for how to deal with it.
Its chair, Labour MP Meg Hillier, said: "As we approach Christmas there are thousands of children in temporary accommodation – a salutary reminder of the human cost of policy failure."
The report warned of an "unacceptable shortage" of realistic housing options for homeless people, and said the lack of genuinely affordable housing had exacerbated the rise in homelessness in the first place.
As of June this year, there were 78,180 households in England – including more than 120,000 children – who had lost their homes and been placed in temporary accommodation, which is often of a very poor standard.
The number of these households has risen by 63% since the end of 2010, and the number of children by 73%, according to official figures. In addition, an unknown number of "hidden homeless" people are housed by family and friends, or moving between hostels and the streets.
Meanwhile the number of people officially counted as sleeping rough has more than doubled to 4,134. Yet charities say the real number is far higher; Crisis estimates that 9,100 people were sleeping rough at any one time in 2016.
The report, released on Wednesday, warned that homelessness had a devastating impact on those who experience it. The average rough sleeper dies before the age of 50, and children in long-term temporary accommodation miss far more schooling than their peers.
"The Department for Communities and Local Government’s attitude to reducing homelessness has been unacceptably complacent," the report said. "The limited action that it has taken has lacked the urgency that is so badly needed and its 'light touch' approach to working with the local authorities tackling homelessness has clearly failed."
The MPs called for an urgent focus across the government on tackling both the supply and affordability of decent housing, in a bid to address the root causes of homelessness.
Hillier said: "The evidence we heard from organisations that work with homeless people should serve as a wake-up call: Government decisions are not made in a vacuum and the consequences can be severe.
"The government must do more to understand and measure the real-world costs and causes of homelessness and put in place the joined-up strategy that is so desperately needed."
Labour's shadow housing secretary, John Healey, said the report showed that "the Conservatives have caused the crisis of rapidly rising homelessness but have no plan to fix it".
He added: "This Christmas, the increase in homelessness is visible in almost every town and city in the country, but today’s report confirms ministers lack both an understanding of the problem and any urgency in finding solutions."
Jon Sparkes, chief executive of Crisis, said he welcomed the government's new "homelessness reduction taskforce", launched in the Budget last month.
"Now the taskforce must quickly get to work and take forward the recommendations of this report, particularly to ensure that welfare reform tackles rather than causes homelessness, and also to join the government’s housing strategy with the need for truly affordable homes for homeless people," he said.
Polly Neate, head of the housing charity Shelter, blamed a "chronic lack of genuinely affordable homes combined with soaring rents and cuts to welfare". She said: "The government must now take heed of this important report and tackle the causes of the crisis by building many more homes which are genuinely affordable for ordinary people to rent.”
A government spokesman said: "Tackling homelessness is a complex issue with no single solution, but we are determined to help the most vulnerable in society.
"That’s why we are providing over £1 billion up to 2020 to reduce all forms of homelessness and rough sleeping and we are bringing in the Homelessness Reduction Act, which is the most ambitious reform in decades, to ensure people get support sooner.
"In addition, we have established a Rough Sleeping and Homelessness Reduction Taskforce across government, with support from experts, so we can respond as effectively as possible."