The Salvation Army has warned of a homelessness crisis if the Government takes a "short-term approach" to spending on support services.
In its report, 'Future-Proof the Roof', The Salvation Army warns that homelessness levels will only increase if the Government does not invest in measures aimed at permanently reducing homelessness and rough sleeping.
It also suggests that a short-term approach will only end up costing the Government more in the long run, with the placement of thousands of families in temporary accommodation expected to leave local authorities with a bill running into the billions of pounds each year.
The Church and charity wants the Government's upcoming Comprehensive Spending Review (CSR) to include adequate funding for homeless services to prevent more people falling into homelessness and ensure that those who have been temporarily housed during lockdown or over winter do not end up back on the streets again after Christmas.
Lorrita Johnson, the Salvation Army's newly appointed Director of Homelessness Services, said: "We understand why the Chancellor has to make big short-term spending commitments to tackle the economic fall out of the pandemic, but he will be racking up a huge bill in the future if he fails to make a long-term investment in homelessness and rough sleeping services.
"Failing to properly address the last decade of underinvestment in this CSR will also have a massive human cost as thousands will lose their homes and be unable to find alternative accommodation."
The Salvation Army has warned that this winter could see even higher levels of rough sleeping because social distancing measures are making it hard to open the traditional winter night shelters, which rely on shared facilities.
Ms Johnson, continued: "The Government must act bravely and invest now to prevent thousands sleeping rough this Christmas, and many thousands more being made homeless, over the remainder of this Parliament and beyond.
"The CSR is a once in a generation opportunity for the Government to change the lives of rough sleepers temporarily housed during the lockdown, and to achieve its manifesto commitment of ending rough sleeping by the end of this Parliament.
This can only happen through a mix of emergency provision during the cold winter months and long-term investment in housing and support to help people tackle the complex reasons why they ended up on the streets.
"It is only through joined up urgent provision now, like we saw through the lockdown, backed up by longer-term investment to tackle the reasons why people are homeless in the first place, that the country will avoid sleep-walking into a homelessness crisis."