A Greater Manchester Charity is among a host warning the country is sleepwalking into a homelessness crisis, with the number of people sleeping rough having doubled over the past five years.
Some say the figure could be even higher because of the difficulty in counting those who are bedding down on Britain's streets.
The charities blame welfare cuts, high rents and low income.
One says the situation is being aggravated by the easy availability of "legal highs".
In a special investigation, Sky News spent the night in one town where homeless men and women were found sleeping under bridges, in car parks and even in rubbish bins.
Using infrared cameras, we revealed the night-time conditions in several highly dangerous locations used by the rough sleepers including caves leading to a sheer drop into a river.
After becoming addicted to drugs and alcohol, Emma Vellino, 31, became homeless and ended up sleeping in the caves.
Earlier this year she broke her spine after falling into the river Mersey. It took five fire engines, two police cars and two ambulances to rescue her in a two-hour operation.
She told Sky News: "I'd been sleeping in the caves for about seven years on and off. I was moving around and next minute I was on the floor of the riverbank. I fell 30 feet and I tried to get back up... I was there for three hours."
Stockport-based charity Wellspring says that in recent years several people have died on the streets of Stockport in Greater Manchester alone.
One was Stefan Tomkins, who was crushed to death aged 31 after the dustbin in which he was sleeping was loaded onto a bin lorry.
Sky News joined Wellspring's project manager, Jonathan Billings, as he helped to carry out the charity's regular 'audit' of rough sleepers in Stockport.
At locations just yards from busy thoroughfares in the town, he showed us dozens of discarded needles and empty canisters of nitrous oxide or so-called hippy crack.
"Legal highs are seriously aggravating an already desperate situation," he told us. "They are an increasing problem... the whole situation around them is getting out of control."
National charities for the homeless have called for decisive political action to tackle what they describe as the severe shortage of affordable homes.
Jon Sparkes, chief executive of Crisis, said: "England is sleepwalking into a homelessness crisis, with a 55% rise in rough sleeping since 2010 and a 14% rise in the past year alone.
"More and more households are struggling to pay their rent in an increasingly insecure market, while cuts to housing benefit and homelessness services have left the safety net in tatters. For anyone finding themselves in financial difficulty, the prospects are bleak."